Question

Mong mọi người giúp đỡ ạ

Answer 1

\(a)7x-21=0.\\ \Leftrightarrow x=3.\)

\(b)3x-5=2x+7.\\ \Leftrightarrow x=12.\)

\(c)6x+18=0.\\ \Leftrightarrow x=-3.\\ d)5x+2=4x-1.\\ \Leftrightarrow x=-3.\)

Answer 2

Bài 1: 

a: 7x-21=0

=>7x=21

hay x=3

b: 3x-5=2x+7

=>3x-2x=7+5

=>x=12

c: 6x+18=0

=>6x=-18

hay x=-3

d: 5x+2=4x-1

=>5x-4x=-1-2

=>x=-3