f(x + 3) = 2x² + 9x + 13
substitute x = x + 3 into f(x)
f(x + 3) = 2(x + 3)² - 3(x + 3) + 4 = 2(x² + 6x + 9) - 3x - 9 + 4
f(x + 3 ) = 2x² + 12x + 18 - 3x - 9 + 4 = 2x² + 9x + 13
