Step-by-step explanation:
well, the approach is totally simple : we use (x+3) everywhere where we have "x" in the function expression.
so,
f(x+3) = 2(x+3)² - 3(x+3) + 4 =
= 2(x² + 6x + 9) - 3x - 9 + 4 =
= 2x² + 12x + 18 - 3x - 9 + 4 =
= 2x² + 9x + 13
