Question

Qual o valor de x tal que f(x)=120 , sendo a função f(x)= 4x -8 ?

Answer 1

Resposta:

1) f(x) = –2x + 3 => f(1) = –2(1) + 3 => f(1) = –2 + 3 =>f(1) = + 1

2) f(x) = 4x + 5 => 7 = 4x + 5 => -4x = +5 - 7 => -4x = -2 =>

3)

f(x) = ax + b

f(1) = 5 => x = 1 e f(x) = 5 => 5 = a + b

f(-3) = -7 => x = -3 e f(x) = 5 => -7 = a + b => -7 = -2a + b

a + b = 5 => a + 1 = 5 => a = 5 -1 => a = 4

f(x) = 4x +1