Question

Determine os zeros das seguintes funções do 1 grau:

a) y=×-3
b) y=2×+1
c) y=4-2×
d) y=-7×+7
e) y=×+5
f) y=1/2×-2

Answer 1

Basta substituir 'y' por 0:

a)

$y=x-3\\\\ 0=x-3\\\\ 3=x\\\\ x=3$

b)

$y=2x+1\\\\ 0=2x+1\\\\ -1=2x\\\\ 2x=-1\\\\ x=-\frac{1}{2}$

c)

$y=4-2x\\\\ 0=4-2x\\\\ -4=-2x\\\\ 4=2x\\\\ 2x=4\\\\ x=\frac{4}{2}\\\\ x=2$

d)

$y=-7x+7\\\\ 0=-7x+7\\\\ -7=-7x\\\\ 7=7x\\\\ 7x=7\\\\ x=\frac{7}{7}\\\\ x=1$

e)

$y=x+5\\\\ 0=x+5\\\\ -5=x\\\\ x=-5$

f)

$y=\frac{1}{2}x-2\\\\ 0=\frac{1}{2}x-2$

Multiplicando ambos os lados da equação por 2:

$0=x-4\\\\ 4=x\\\\ x=4$