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3 years ago

Factor the following difference of perfect squares x^2-81

Mathematics

2 answers:

Margarita [4]3 years ago

7 0

Answer:

(x+9)(X-9)

Step-by-step explanation:

Brrunno [24]3 years ago

5 0

Since both terms are perfect squares, factor using the difference of squares formula, a ^2 − b^ 2 = ( a + b ) ( a − b ) where a = x and b = 9 . ( x + 9 ) ( x − 9 )

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Two students are reading a novel. Ashley reads 10 pages per day. Carly reads 8 pages per day, but she starts early and is alread

Alecsey [184]

Is there more options because somethings missing

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3 years ago

School A has 480 students and 16 classrooms. School B has 192 students and 12 classrooms.

boyakko [2]

Answer:96

Step-by-step explanation:

A; 480/16 = 30 students per classroom

B: 192/12 =16 students per classroom

we need x such that $\frac{480-x}{16} = \frac{192+x}{12}$

which means

(480-x )* 12 should be equal to (192+x) * 16

5,760 - 12x = 3,072+16x

5,760 - 3,072 = 12x + 16x

2,688 = 28x

x = 96

3 0

3 years ago

Find the area of a circle with a diameter of four

Elis [28]

Answer:

12.57

Step-by-step explanation:

the formula for the area of a circle is $\pi r^{2}$

the diameter is 2 times the radius, so dividing it by 2 gives you a radius of 2

substitute the 2 for the r in the formula and solve

$\pi 2^{2}$

4 $\pi$

≈12.57

7 0

3 years ago

Read 2 more answers

The slipe of the line passing through the points (7, 5) and (21, 15) is

SOVA2 [1]

Answer:

5/7

Step-by-step explanation:

You find a slope by using the equation y2-y1/x2-x1.

In this case: 15-5/21-7

10/14

5/7

6 0

3 years ago

You have 42 ft. of fencing (1 ft. segments) to make a rectangular garden. How much should each side be to maximize your total ar

Verizon [17]

Answer:

$Length=10.5\ ft$

$Width=10.5\ ft$

$Area=110.25\ ft^{2}$

Step-by-step explanation:

Let

x----> the length of the rectangular garden

y---> the width of the rectangular garden

we know that

The perimeter of the rectangle is equal to

$P=2(x+y)$

we have

$P=42\ ft$

$42=2(x+y)$

simplify

$21=(x+y)$

$y=21-x$ ------> equation A

Remember that the area of rectangle is equal to

$A=xy$ ----> equation B

substitute equation A in equation B

$A=x(21-x)$

$A=21x-x^{2}$ ----> this is a vertical parabola open downward

The vertex is a maximum

The y-coordinate of the vertex is the maximum area

The x-coordinate of the vertex is the length side of the rectangle that maximize the area

using a graphing tool

The vertex is the point $(10.5,110.25)$

see the attached figure

$x=10.5\ ft$

Find the value of y

$y=21-10.5=10.5\ ft$

The garden is a square

the area is equal to

$A=(10.5)(10.5)=110.25\ ft^{2}$ ----> is equal to the y-coordinate of the vertex is correct

6 0

3 years ago