Answer :
f(x) = x² + 2x + 1
f(x + h - f(x))
f((x² + 2x + 1) + (1 + 2 + 1) - f(x² + 2x + 1)))
f((x² + 2x + (1 + 1 + 2 + 1) - f(x² + 2x + 1)))
f((x² + 2x + 5) - f(x² + 2x + 1))
f(x² - x² + 2x - 2x + 5 - 1)
f(4)
f(4) = 4² + 2(4) + 1
f(4) = 16 + 8 + 1
f(4) = 25
f(x + h - f(x))
f((x² + 2x + 1) + (1 + 2 + 1) - f(x² + 2x + 1)))
f((x² + 2x + (1 + 1 + 2 + 1) - f(x² + 2x + 1)))
f((x² + 2x + 5) - f(x² + 2x + 1))
f(x² - x² + 2x - 2x + 5 - 1)
f(4)
f(4) = 4² + 2(4) + 1
f(4) = 16 + 8 + 1
f(4) = 25
