Diketahui rumus fungsi f (x) = 4x – 12. Jika f (a) = 8 dan f (-2) = b , maka nilai a + b adalah ....

f(x) = 4x-12
f(a) = 4a-12 = 8
4a = 8+12
4a = 20
a = 5

f(-2) = 4×(-2)-12 =b
-8-12 = b
-20 = b
b = -20

a + b = 5 + (-20)
= -15.

maaf kalo ada yg salahhh

jawabanya 0

f(x)= 4x-12
f(a)= 4(a)-12=8
       
a=20

f(x)= 4x-12
f(-2)= 4(-2)-12=b

b=-20

a+b=20+(-20)=0