Jika diketahui fungsi-fungsi f(x)=5x+6 g(x)=-3x+12

a. 2x + 18, b. -8x + 6, c. -15x² + 42x + 72

Pembahasan

Diketahui fungsi-fungsi:
f(x) = 5x + 6
g(x) = -3x + 12

a. Tentukanlah f(x) + g(x):
   f(x) + g(x) = (5x + 6) + (-3x + 12)
              = 5x + 6 - 3x + 12
              = (5x - 3x) + (6 + 12)
              = 2x + 18

b. Tentukanlah g(x) - f(x):
   g(x) - f(x) = (-3x + 12) - (5x + 6)
              = -3x + 12 - 5x - 6
              = (-3x - 5x) + (12 - 6)
              = -8x + 6

c. Tentukanlah f(x) . g(x):
   f(x) . g(x) = (5x + 6) . (-3x + 12)
              = 5x(-3x + 12) + 6(-3x + 12)
              = -15x² + 60x - 18x + 72
              = -15x² + (60x - 18x) + 72
              = -15x² + 42x + 72