Question

Who honestly knows how to do this? The length of a rectangle is 4 less than three times the width. If the perimeter of the rectangle is 48, write an equation to represent this situation.

Use x for the variable.
Width Expression:
Length Expression:
Equation:

Answer 1

• width: x
• length: 3x-4
• equation: 8x-8 = 48

There are other forms you could input for the equation

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Step-by-step explanation:

length = 3*(width) - 4

length = 3x - 4

where we let "x" take the place of "width".

This means 3x-4 will go in the "length expression" box, while x goes in the "width expression" box.

P = perimeter of rectangle

P = 2*(length+width)

P = 2*(L+W)

P = 2*(3x-4+x)

P = 2*(4x-4)

P = 8x-8

Set this equal to the stated perimeter of 48 to end up with the equation 8x-8 = 48

Other equations are possible.

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Extra info:

Solving that last equation for x gets you x = 7, and it leads to 3x-4 = 3*7-4 = 17.

Therefore, this is an 17 by 7 rectangle. Perimeter = 17+7+17+7 = 48 which confirms we have the correct equations above, and correct rectangle dimensions.