Question

Determine f(x)=ax+b, sabendo que:

a) f(1)= 2 e f(3)= -2

Answer 1

2 = a . 1 + b ; 2 - a = b ; - 2 = a . 3 + b ; - 2 = 3a + 2 - a ; - 2 - 2 = 2a; -4 = 2a ; -4:2 = a ; a = -2; b = 2 - a; b = 2 - (-2); b = 2 + 2 = 4; Portanto f (x ) = - 2x + 4