Dik:f(x)=ax+b f(1)=-6 f (2)=7 dit = f (x)= f(3)=

F(x)=ax+b
f(1)=(1)a+b=-6
f(2)=2a+b= 7
___________(-)
-a =-13
a = 13
f(1)=13+b=-6
b=-6-13=-19
f(x)=13x-19
f(3)=13(3)-19=39-19=20