Question

Dik : sebuah f(x) = 2x^2+3x+5
tentukan :
a. f(a)
b. f(a-1)
c. f(-2)
d. f(1/2)

Answer 1

A.) f(a) = 2a^2 + 3a + 5
b.) f(a-1) = [2 x (a-1)^2] + 3 (a-1) +5
= [2 (a^2 - 2a + 2)] + ( 3a - 3) + 5
=2a^2 - 4a + 4 +3a - 3 + 5
= 2^2 - a + 6
c.) f(-2) = 2 (-2)^2 + 3(-2) + 5
= 2 (4) + (-6) + 5
= 8 - 6 + 5
= 7
d.) f(1/2) = 2 (1/2)^2 + 3(1/2) + 5
= 2 (1/4) + 3/2 + 5
= 1/2 + 3/2 + 10/2
= 14/2
= 7