Explanation:
(f + g)(x) = f(x) + g(x)
= (2x² - 9x) + (3x - 2) = 2x² - 6x - 2.
Therefore (f + g)(3) = 2(3)² - 6(3) - 2 = -2.
(f - g)(x) = f(x) - g(x)
= (2x² - 9x) - (3x - 2) = 2x² - 12x + 2.
Therefore (f - g)(-4) = 2(-4)² - 12(-4) + 2 = 82.
(g o f)(x)
= g(2x² - 9x) = 3(2x² - 9x) - 2 = 6x² - 27x -2.
(f o g)(x)
= f(3x - 2) = 2(3x - 2)² - 9(3x - 2) = 18x² - 51x + 26.