Answer: (a) P = 6W + 2
(b) L = 2W + 1
(c) Width = 13cm
Length = 27cm
Step-by-step explanation:
The formula for perimeter of a rectangle is 2(length + width). Since the length is 1 cm more than twice its width, then the length will be:
L = (2 × W) + 1
(b) L = 2W + 1
Therefore, P = 2(L + W)
P = 2( 2W + 1) + 2W
P = 4W + 2 + 2W
(a) P = 6W + 2
Since perimeter is given as 80cm. Therefore,
P = 6W + 2
6W + 2 = 80
6W = 80 - 2
6W = 78
W = 78/6
W = 13
Width is 13cm
Length = 2W + 1
Length = 2(13) + 1
Length = 27cm
Answer: -10
Step-by-step explanation:
Simplifying
-3(y + 5) = 15
Reorder the terms:
-3(5 + y) = 15
(5 * -3 + y * -3) = 15
(-15 + -3y) = 15
Solving
-15 + -3y = 15
Solving for variable 'y'.
Move all terms containing y to the left, all other terms to the right.
Add '15' to each side of the equation.
-15 + 15 + -3y = 15 + 15
Combine like terms: -15 + 15 = 0
0 + -3y = 15 + 15
-3y = 15 + 15
Combine like terms: 15 + 15 = 30
-3y = 30
Divide each side by '-3'.
y = -10
Simplifying
Answer:
P = -4
Step-by-step explanation:
Assuming that x = 20 and y = 24, you have to plug in these numbers for x and y to get to this equation P = 20 - 24. You should get -4 when you subtract 24 from 20 giving you a negative answer.
Answer:
Step-by-step explanation:
A product is formed by multiplying the factors. Here, you want the product of -2 and x, so that is indicated as ...
-2x
You want that product greater than 30. The symbol for "greater than" is >, so you have ...
-2x > 30 . . . . the desired inequality
__
The most straightforward way to solve this is to divide by the coefficient of x. Because that is negative, you must reverse the inequality symbol from "greater than" to "less than."
x < 30/(-2)
x < -15 . . . . . . the desired solution
_____
<em>Additional comment</em>
It may not be clear why multiplying or dividing an inequality causes the symbol to be reversed. You can think of it as reflecting the inequality over the point x=0 on the number line. Where larger numbers were on the right, they get reflected to points farther left, so as negative numbers, they are smaller numbers.
Consider ...
1 < 2
-1 > -2
