Question

Diketahui fungsi f(x) = 3x + 10. jika f(-1) = a dan f(b)= -2, nilai a+b adalah

Answer 1

F(x) = 3x + 10

f(-1) = a

f(-1) = 3(-1) + 10
a     = -3 + 10
a     = 7

f(b) = -2

f(b) = 3b + 10
-2 = 3b + 10
-2 - 10 = 3b
-12 = 3b
-4 = b

a + b
7 + (-4)
7 - 4
3

Answer 2

F(-1) = 3.(-1) + 10 = a 
a = -3 + 10 
a = 7 
f(b) = 3b + 10 = -2
3b = -2 -10
3b = -12
b = -12 : 3
b = -4

jadi, a + b 
= 7 + (-4)
= 3