Question

Determine algebricamente o zero das seguintes funções do 1º grau:

a) f (x) = 2x - 8
b) f (x) = 5x
c) f (x) = 2/3x + 1
d) f (x) = 4 - 5/2 x

Answer 1

$a) 2x-8=0 \\ x= \frac{8}{2} =4 \\ \\ b)5x=0 \\ x=0 \\ \\ c) \frac{2}{3} x+1=0 \\ \\ \frac{2}{3}x=-1 \\ \\ x=-1. \frac{3}{2} =- \frac{3}{2} \\ \\ d)4- \frac{5}{2} x=0 \\ \\ 4= \frac{5}{2}x \\ \\ x=4. \frac{2}{5} \\ \\ x= \frac{8}{5}$

Answer 2

a) f(x) = 2x - 8
2x - 8 = 0
2x = 8
x = 8/2
x = 4

b) f(x) = 5x
5x = 0
x = 0/5
x = 0

c) f(x) = 2/3x + 1
2/3x + 1 = 0
2/3x = -1
x = -1 .  3
           2
x = -3/2

d)f(x) = 4 - 5/2x
4 - 5/2x = 0
-5/2x = -4
x = -4 . 2
          -5
x = -8/-5
x = 8/5