Question 91310
Write an equation for the length in terms of width:
Equation #1: {{{L=5W+1}}}
Write an expression for the Area:
Equation #2: {{{LW=89}}}
Now you have 2 equations with 2 unknowns. Any time you have at lease as many equations as you have unknowns, you can find the unknowns!
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Substitute the value of L from Equation #1 into Equation #2:
{{{(5W+1)W=89}}}
{{{5W^2+W-89=0}}}
Apply the quadratic formula:
{{{W=(-1+-sqrt(1^2-(4*5*(-89))))/(2*5)}}}
{{{W=(-1+-sqrt(1781))/10}}}
W=(-1+-42.2)/10
W=4.12,W=-4.32
The width needs to be positive, so throw out the negative result:
{{{highlight(W=4.12)}}}
Now, substitute this value of W into Equation #1 to find L.
I will leave that part to you :-)
Goos Luck,
tutor_paul@yahoo.com