1)
(2x-5)(x+4)
Set each to 0
2x-5=0
x+4=0
This will get you x=-4 or x=5/2
Hope this helped!
Larger rectangle area = L x W = 3x ( x-2) = 3x^2 -6x
Smaller area = x (x-4) = x^2 - 4x summed = 36 (given)
3x^2 - 6x + x^2 - 4x = 36 combining terms
4x^2 - 10x - 36 = 0 divide through by 2
2x^2 - 5x - 18 = 0 solve for 'x' with quadratic formula or factoring
(2x - 9) (x +2) = 0 so x = 9/2 or -2 (throw out)