a text book store sold a combined total of 411 psychology and math textbooks in a week. the number of math textbooks sold was 63 less than the number of psychology textbooks sold. how many textbooks of each typer were sold

Answer:

uhh 7 people joined?

Step-by-step explanation:

Answer:

7

Step-by-step explanation:

from 56 people to 63 people theres 7

56 - 63 is 7

Answer:

6 miles

Step-by-step explanation:

x = miles driven

4.00 + 2.75 * x = 20.50

2.75x = 20.50 - 4.00 = 16.50

so

x = 16.50/2.75 = 6 miles

Answer:

4.5km/h

Step-by-step explanation:

Here we know that she does 9 km per 2 hours. If we know how much she can travel in 2 hours it's very easy to find out how much she travels in 1. Because half of 2 hours is one hour. So we can simply half 9 km to find how much she travels in 1 hour:

9/2 = 4.5

4.5km/h

I hope this makes sense :)

Answer:

4.5 km per hour

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the answer is : 9.72×10^4 or 972×10^2

Step-by-step explanation:

l didn't agree with the answer because

(1.72×10^4 + 8×10^4)

form above take common i.e., 10^4 so we get,

10^4 (1.72+8.00)

10^4(9.72)

so we get the answer is : 9.72×10^4 or

(972÷100)10^4

972 × 10^-2 ×10^4

972× 10^(-2+4)

972× 10^2

Answer:

1

Step-by-step explanation:

8²-15/7²

64-15/49

49/49

1

Hope this helps :)

Answer:

19

Step-by-step explanation:

because you inverse the operation

5 ×3 = 15

15 + 4 = 19

Answer:

8 is 50% of 16

Step-by-step explanation:

since 8 is half of 16

Answer:

q = 6

Step-by-step explanation:

30/5 = 6

5(6)/5

30/5

6

Have an amazing day!!

PLEASE RATE AND MARK BRAINLIEST!!!

Answer: 98 degrees

Step-by-step explanation:

The exterior angle theorem states that the measure of an exterior angle is equal to the sum of the measures of the two remote interior angles of the triangle.

Therefore: x + 3x+2 = 130

Combining like terms gives: 4x+2 = 130

Solving for x: x = 32

Substituting the value of x for the value of angle C: 3(32) +2

Simplifying: 98 degrees.

Answer:

C

Step-by-step explanation:

Explanation is on picture.

Hope that helps :)

Answer:

c

Step-by-step explanation:

you can only simplify this part

[tex]5x\sqrt{2} +x\sqrt{2} =6x\sqrt{2}[/tex]

so the rest would remain the same

The scale factor used to represent the model from the real object size is y = (260/3)x

An equation is an expression that shows the relationship between two or more numbers and variables.

Let y represent the real object size and x represent the size of the model.

Given that:

y = (260/3)x

The scale factor used to represent the model from the real object size is y = (260/3)x

Find out more on equation at: https://brainly.com/question/2972832

Answer:

26.38°  (nearest hundredth)

30.7960166... hours = 30 hours 47 mins 37 secs

Step-by-step explanation:

one knot = one nautical mile (nm) per hour

Therefore, 15-knot speed for 10 hours = 15 × 10 = 150 nm

Use cosine rule to find the distance between the ship and Barbados (blue dashed line on attached diagram).

Cosine rule:   c² = a² + b² - 2ab cos(C)

Given:

⇒ c² = 150² + 600² - 2(150)(600)cos(20°)

⇒ c² = 213355.3283...

⇒ c = 461.9040249... nm

Use sine rule to calculate smallest missing angle (red on attached diagram)

[tex]\sf \implies \dfrac{sin(A)}{150}=\dfrac{sin(20)}{461.9040249}[/tex]

[tex]\sf \implies sin(A)=\dfrac{150sin(20)}{461.9040249}[/tex]

[tex]\sf \implies A=6.376917848... \textdegree[/tex]

Sum of interior angles of a triangle = 180°

⇒ missing interior angle (green) = 180° - 20° - 6.376917848...° = 153.6230822...°

Angles on a straight line sum to 180°

⇒ x° = 180° - 153.6230822...° = 26.376917848...°

The distance between the Ship and Barbados is 461.9040249 nm

Therefore, to calculate the time, divide the distance by the speed:

t = 461.9040249... ÷ 15 = 30.7960166... hours

Answer:

$22

Step-by-step explanation:

2x5.00=$10     4x3.00=$12

10+12=22

Answer:

$22.00

Step-by-step explanation:

5 x 2 = 10

3 x 4 = 12

total = $22.00

I think your question seems like :-

Find the maximum and minimum values of f(x,y) = 2+2x+4y-x²-y² on the triangular region in the first quadrant bounded by the lines x = 0, y = 0, y = 9-x. The reason is below :

If you see carefully, the given lines were x = 0, y = 0, y = 9x , also these lines forms a Triangle in first quadrant (Given) , but these all lines doesn't form a triangle in 1st quadrant , we can't change the other two lines (As those two lines will work as permanent sides and support for the triangle) but third one can be , also neither 9 + x nor (9/x) can't form triangle in 1st quadrant with the given other two lines .Only with y = 9 - x the given situation can be achieved

But before starting the question let's recall some of the concepts :-

For a given function let it be f(x,y) ,

Where ,

Now , consider the function ;

[tex]{:\implies \quad \sf f(x,y)=2+2x+4y-x^{2}-y^{2}}[/tex]

Partial Differentiating both sides w.r.t.x

[tex]{:\implies \quad \sf \dfrac{\partial f}{\partial x}=2-2x}[/tex]

Now , partial differentiating both sides w.r.t.y

[tex]{:\implies \quad \sf \dfrac{\partial^{2}f}{\partial x\partial y}=0}[/tex]

Now , consider ;

[tex]{:\implies \quad \sf \dfrac{\partial f}{\partial x}=2-2x}[/tex]

Partial differentiating both sides w.r.t.x

[tex]{:\implies \quad \sf \dfrac{\partial^{2}f}{\partial x^{2}}=-2}[/tex]

Now , consider ;

[tex]{:\implies \quad \sf f(x,y)=2+2x+4y-x^{2}-y^{2}}[/tex]

Partial differentiating both sides w.r.t.y

[tex]{:\implies \quad \sf \dfrac{\partial f}{\partial y}=4-2y}[/tex]

Now , partial differentiating both sides w.r.t.y

[tex]{:\implies \quad \sf \dfrac{\partial^{2}f}{\partial y^{2}}=-2}[/tex]

Now to find the critical points , first order partial derivative of f(x,y) both w.r.t.x and w.r.t.y must be 0. So , if you equate them to 0 , you will get x = 1 and y = 2. So critical point is only one i.e (1,2)

Now , from the above conditions , let calculate AC - B² first , from which we will get maxima or minima

[tex]{:\implies \quad \sf (-2)(-2)-(0)^{2}}[/tex]

[tex]{:\implies \quad \sf 4\> 0}[/tex]

So , AC - B² > 0 and also A < 0 , so maxima at (1,2) , to find maxima we need to put x = 1 , y = 2 in f(x,y) i.e f(1,2) = 2 + 2(1) + 4(2) - 1² - 2² = 7 . Now , for minima , draw the triangle see attachment 1 . Now , in the attachment critical points are (0,9) , (0,0) and (9,0) . Now , we need to find f(x,y) at these all points too . If you calculate then you will get f(0,9) = -43 , f(0,0) = 2 and f(9,0) = -61 , out of which -61 is minimum

So , the required maxima and minima are 7 and -61

Note :- Also , refer to the attachments no. 2,3,4 as well for why I choosed the third line to be 9 - x rather than others.

(5,-12) is located in the fourth quadrant.

Because 5 being positive and 12 being negative it lies in the 4th quadrant.

Step-by-step explanation:

Answer:

Lines C and D

Lines A and B

Step-by-step explanation:

Parallel lines are two straight lines that never intersect with one another.

Lines C and D are parallel because they are straight and will never intersect

Lines A and B are parallel because they are straight and will never intersect

Answer:

a 30÷5=6

Step-by-step explanation:

Because from the fact the numbers that were used were 5,6and30.

they solved for 5×6=30,30÷6=5and6×5=30. which means it is left with 30÷5=6.

hope this helps.

Answer:

?=5

Step-by-step explanation:

4/5-2/5=2/5

First we must replace ? with x for an unknown value and then solve.

Answer:

7

Step-by-step explanation:

The letter for sausage or red sauce is S at the end and R in the middle.

Counting, there is 7 outcomes that have either S at the end or R in the middle.

Answer:

1

Step-by-step explanation:

Multiply -4 with 2x and -7

Then collect like terms

Divide both sides by the co-efficient of x

Step-by-step explanation:

3% = 0.03

we are looking for the 3rd percentile of Z.

checking the Z-table we find as the entry closest to 0.03 to be 0.0301 at z = -1.8 and 0.8.

so, the 3rd percentile of Z is -1.88

the cutoff number (the number of miles, where max. 3% of the tires will qualify for a refund) is

mean value + Z× standard deviation

22000 + -1.88 × 3100 = 16,172 ≈ 16,170

so, b. is correct

The way the angles are labeled tell you that they are all congruent. The two triangles you see here also share the side that joins them. Then by the angle-side-angle postulate, the two triangles are congruent, so x + 23 = 13, or x = -10.

Answer:

k≥12

Step-by-step explanation:

if k's smallest amount is 12, k has to be bigger (greater than) or equal to 12

therefore:

k≥12

Answer:

The sum is 12276 . 

Step-by-step explanation:

This expression can be written as:Σ10i=1(6×2n)=6×Σ10i=12n

The last expression is a sum of a finite geometrical sequence for which: a1=2,q=2,n=10. This sum can be calculated as:S10=2×1−2101−2=2×210−12−1=2×(210−1)==2×1023=2046So the value of the first expression is: 6×2046=12276

Mark me brainliest!!

Answer:

4.5 cm

Step-by-step explanation:

Circunference = 2π*radius = 2*3.14*radius = 6.28*radius = 28.26

so radius = 28.26/6.28 = 4.5 cm

Answer:

i am not really sure but

Step-by-step explanation:

Answer: C

Step-by-step explanation:

The equation of a parabola in vertex form is

y = a(x - h)² + k

where (h, k) are the coordinates of the vertex and a is a multiplier

Here (h, k) = (3, - 0.5), thus

y = a(x - 3)² - 0.5

To find a substitute either of the x- intercepts into the equation.

Using (4, 0), then

0 = a(4 - 3)² - 0.5 = a - 0.5 ( add 0.5 to both sides )

a = 0.5

y = 0.5(x - 3)² - 0.5 ← equation of quadratic function