a²+2a-15. The product of (a+5)(a-3) is equal to a²+2a-15.
The given expression (a+x) (a-y) is a product of two binomials, where you can see that a is a term that is in both binomials, which is why it is said to be a common term. Its solution is (a+x) (a-y) = a(a-y)+x(a-y) = a²-ay+ax+x(-y)=a²(x-y)a+x(-y).
for this problem, we have (a+5)(a-3) where x = 5 and y = -3.
Substituting the vaues in the equation (a+x) (a-y) = a²(x-y)a+x(-y):
(a+5)(a-3) = a²(5-3)a+(5)(-3) = a²+2a-15
