Question

Determine a raiz ou zero das seguintes funções do 1º grau:
a) y= -3x-6
b) y=-5x+15
c) y=7x
d) y=-x-1
e) y= 2\5x + 1
f) y= -3\4x +2\5

Answer 1

a) y= -3x-6 ==> -3x - 6 = 0 ==> 3x = - 6 ==> x = - 2

b) y=-5x+15 ==> -5x + 15 = 0 ==> 5x = 15 ==> x = 3

c) y=7x ==> 7x = 0 ==> x = 0

d) y=-x-1 ==> - x - 1 = 0 ==> x = - 1
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e) y= 2\5x + 1==> 2x + 1 = 0=> 2x + 5 = 0 ==> 2x= -5 ==> x = -5/2 
                              5
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f) y= -3\4x +2\5 ==> - 3x + 2 = 0 => -15x + 8 = 0 ==> 15x = 8 ==> x= 8/15
                                    4    5