Question 248260
40=L*W
L=6+W
substitute 6+w for L in 40=L*W to get 40=(6+W)*W
40=(6+W)*W
40=6W+W^2
subtract 40 from both sides and move everything to the opposite sides
W^2+6W-40=0
to factor we need factors of 40 that are different by 6
factors of 40
40*1;20*2;10*4;5*8
which ones are different by 6
10 and 4
we need positive six so we need 10-4
(x-4)(x+10)=0
x=4 and x=-10
*[invoke quadratic "x", 1, 6, -40 ]