Question

Se F (1)=-1 e F(2)=2.Calcule F (-1)=?

Answer 1

f(x)=ax+b

f(1)=-1
a.1+b=-1
a+b=-1

f(2)=2
a.2+b=2
2a+b=2

a+b=-1
2a+b=2

-a-b=1
2a+b=2
_______
a+0=3
a=3

a+b=-1
3+b=-1
b=-1-3
b=-4

f(x)=3x-4
f(-1)=3.(-1)-4=-3-4=-7
f(-1)=-7