Question 199746
A(x) = x^2 +5x +6
.
a(5) = (5)^2 + 5(5) +6 = 56
.
A(x) = x^2 +5x +6 = 1/2 ( h) (l) = (1/2) (x+3) h,,,,,,,area  of  triangle  =  1/2  base * height
.
{ (x+3)(x+2) } / (1/2) ( x+3) = 2(x+2) = h
.
check
.
A(5) = 56,  (x+3)= 8,, A = 1/2 * 8 * h = 56,,,,,h= 112/8 = 14
.
h=2(x+2) = 2 (5+2) =14,,,,,,ok