Jika
............3x + 1, x < 0
f(x) = { x^2 - 5, 0<=x<=3
............15 + x, x>=3
f(-2) + f(1) + f(5)=
a. 11
b. 19
c. 21
d. 29
e. 31
............3x + 1, x < 0
f(x) = { x^2 - 5, 0<=x<=3
............15 + x, x>=3
f(-2) + f(1) + f(5)=
a. 11
b. 19
c. 21
d. 29
e. 31
Matematika SMA Kelas XI
Perhatikan,
Domain x = - 2 berada pada x < 0
Domain x = 1 berada pada interval 0 ≤ x ≤ 3
Domain x = 5 berada pada x > 3
f(- 2) = 3(- 2) + 1
= - 5
f(1) = (1)² - 5
= - 4
f(5) = 15 + 5
= 20
Jadi f(- 2) + f(1) + f(5) = - 5 - 4 + 20 = 11