Question

Dada a função do 1º grau f(x)=1-2x, determine:

a) f(0)
b) f(-1)
c) f(x)=11

Answer 1

Letra A

$\sf f(x) = 1 - 2x$

$\sf f(0) = 1 - 2\cdot 0$

$\sf f(0) = 1 + 0$

$\red{\sf f(0) = 1}$

Letra B

$\sf f(x) = 1 - 2x$

$\sf f( - 1) = 1 - 2\cdot ( - 1)$

$\sf f( - 1) = 1 + 2$

$\red{\sf f( - 1) = 3}$

Letra C

$\sf f(x) = 1 - 2x$

$\sf 11 = 1 - 2x$

$\sf 1 - 2x = 11$

$\sf - 2x = 11 - 1$

$\sf - 2x = 10$

$\sf ( - 2x = 10)\cdot ( - 1)$

$\sf 2x = - 10$

$\sf x = \dfrac{ - 10}{ \: \: \: 2}$

$\red{\sf x = - 5}$