Question 690565
Set-Up
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A = L * W  (Area of a rectangle)
Given: A = 128, L = W + 8
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Solution:
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Substitute the given information into the equation for the area of a rectangle
{{{(128) = (W + 8) * W}}} Simplify
{{{128 = W^2 + 8W}}} Subtract 128 from both sides
{{{0 = W^2 + 8W - 128}}}
Use the quadratic equation

*[invoke quadratic "W", 1, 8, -128]

The answers were W = 8feet or -16feet. but since you can not have a negative width. Just use the 8

Now we can find the length
L =W + 8
Plug 8 in for W
{{{L = 8 +(8)}}}
{{{highlight_green(L = 16 feet)}}}