Find and simplify the expression if f(x) = x^2−10

Question

Find and simplify the expression if f(x) = x^2−10

​f(5+​h) −​ f(5​) = _______

Answer 1

f(5+h) - f(5) = ((5+h)²-10) - (5² - 10)

f(5+h) - f(5) = (h² + 10h + 25 - 10) - (25 - 10)

f(5+h) - f(5) = (h² + 10h + 15) - (15)

f(5+h) - f(5) = h² + 10h + 15 - 15

f(5+h) - f(5) = h² + 10h or h(h+10)