Domain and range of y=-2x^2+12x-15

The length of a rectangle is nine inches more than its width. Its area is 486 square inches. Find the width and length of the re

Elan Coil [88]

Answer:

width: 18 in
length: 27 in

Step-by-step explanation:

The relations between length (L) and width (W) are ...

W +9 = L

LW = 486

Substituting gives ...

(W+9)W = 486

W^2 +9W -486 = 0 . . . put in standard form

(W +27)(W -18) = 0 . . . . factor

W = 18 . . . . the positive solution

The width of the rectangle is 18 inches; the length is 27 inches.

_____

<em>Comment on factoring</em>

There are a number of ways to solve quadratics. Apart from using a graphing calculator, one of the easiest is factoring. Here, we're looking for factors of -486 that have a sum of 9.

486 = 2 × 3^5, so we might guess that the factors of interest are -2·3² = -18 and 3·3² = 27. These turn out to be correct: -18 +27 = 9; (-18)(27) = -486.

3 0

3 years ago

Write an equivalent expression using distributive property and simplify for each question

Lana71 [14]

Answer:

Check explanations

Step-by-step explanation:

For all real numbers a,b, and c, the distributive property states that:

$a(b + c) = ab + ac$

For Part A, we have

$2x + 10x = x(2 + 10) = x(12) = 12x$

Or

$2x + 10x = 2x(1 + 5) = 2x(6) = 12x$

For Part B, we have

-4(3x-10)+5(2-6x)=-4*3x--4*10+5*2-5*6x

This simplifies to:

-4(3x-10)+5(2-6x)=-12x+40+10-30x

-4(3x-10)+5(2-6x)=-12x-30x+40+10

-4(3x-10)+5(2-6x)=-42x+50

For the C part, we have:

$2(x - 4) + x = 2 \times x - 2 \times 4 + x$

$2(x - 4) + x = 2x - 8+ x$

$2(x - 4) + x = 3x - 8$

For Part D, we have:

$-3-7(3-4x)+8x = - 3 - 7 \times 3 - 7 \times - 4x + 8x$

We simplify to get:

$-3-7(3-4x)+8x = - 24+28x + 8x$

Simplify further to get:

$-3-7(3-4x)+8x =-24+36x$

4 0

3 years ago

Jim

stealth61 [152]

yes i agree because if all the integers are positive, the answer stays positive which means if you know your integer rules: a positive divide by a positive it stays positive. its the same thing for all the other operations. hope this helps.

6 0

3 years ago

Read 2 more answers

Can you verify my answer?<br><br> I believe it's reflection.

Anna007 [38]

Yes i think it is reflection try reflection

4 0

3 years ago

Find the perimeter and the area of each shape. Give your answer as a completely simplified exact value in terms of π (no approxi

nydimaria [60]

Answer:

Circumference: 12π + 8 cm,

Area: 48 ( cm )^2

Step-by-step explanation:

This figure is composed of circles, squares, and semicircles. As you can see, the squares indicate that each semicircle should have ( 1 ) the same area, and ( 2 ) the same length ( circumference ). It would be easier to take the circumference of the figure first, as it is composed of arcs part of semicircles the same length.

Circumference of 1 semicircle = $\frac{1}{2}$ ( πd ) = $\frac{1}{2}$ π( 4 ) = 2π ( cm )

Circumference of Figure (composed of 6 semicircles + 2 sides of a square),

We know that 6 semicircles should be 6 $*$ 2π, and as the sides of a square are equal - if one side is 4 cm, the other 3 are 4 cm as well. Therefore the " 2 sides of a square " should be 2

Circumference of Figure = 6 $*$ 2π + 2 = 12π + 8 ( cm )

_____________

The area of this figure is our next target. As you can see, it is composed of 3 semicircles, and the area of 3 semicircles subtracted from the area of 3 squares. Therefore, let us calculate the area of 1 semicircle, and the area of 1 square first.

Area of 1 semicircle = 1/2π $r^2$ = 1/2π $(2)^2$ = 2π ( cm ),

Area of 1 square = ( 4 cm )( 4 cm ) = 16 ( $cm^2$ )

So, the area of the figure should be the following -

Area of Figure = 3 $*$ 2π + 3( 16 - 2π ) = 48 ( cm )^2

3 0

3 years ago