Question

Dada a função f: R em R definida por y = f(x) =2x+9 obtenha

a) f(0)
b) f(-1)
c) f(3)
d) f(1/2)
e) o valor de x quando f(x) = -1

Answer 1

$a) \: f(0) = 2 \times 0 + 9 = 9 \\ \\ b) \: f( - 1) = 2 \times ( - 1) + 9 = - 2 + 9 = 7 \\ \\ c) \: f(3) = 2 \times 3 + 9 = 6 + 9 = 15 \\ \\ d) \: f( \frac{1}{2} ) = 2 \times \frac{1}{2} + 9 = 1 + 9 = 10 \\ \\ e) \: 2x + 9 = - 1 \\ 2x = - 1 - 9 \\ 2x = - 10 \\ x = - \frac{10}{2} \\ x = - 5$