Question 115021
L=W+2
10=L*W
10=(W+2)W
10=W^2+2W
W^2+2W-10=0
USING THE QUADRATIC EQUATION WE GET:
{{{x = (-b +- sqrt( b^2-4*a*c ))/(2*a) }}} 
W=(-2+-SQRT[2^2-4*1*-10])/2*1
W=(-2+-SQRT[4+40])/2
W=(-2+-SQRT44)/2
W=(-2+-6.633)/2
W=-2+6.633)/2
W=4.633/2
W=2.3165 ANSWER FOR THE WIDTH.
L=2.3165+2=4.3165 ANSWER FOR THE LENGTH.
PROOF
2.3165*4.3165=10
10~10