Answer:
C
Step-by-step explanation:
first of all, the correct factorization is
y = (x - 3)(x + 6)
because when we do the multiplication
y = x² + 6x - 3x - 18 = x² + 3x - 18
and then, the factorization tends us also directly the zero points, because y is only 0, when one of the factors is 0.
so, either x-3 or x+6 has to be 0 to make the whole expression 0.
and that is only for x=3 or x=-6
Area of the triangle = (1/2)*base*height
base = x
height = altitude = x+6
Area of the triangle = (1/2)*x*(x+6) = 108
(1/2)*x*(x+6) = 108
x²+6x-216 =0
(x+18)(x-12)=0
x=-18, or x=12
We can use only positive value, so x=12.
Base =12 cm.
I hope this is what you were looking for! x^2 + xn + xm + mn