Решите уравнения 1)х-(50-х)=12 2)х+(х+1)+(х+2)=9 3)21+(20-4х)-(11-2х)=0

Question

Решите уравнения
1)х-(50-х)=12
2)х+(х+1)+(х+2)=9
3)21+(20-4х)-(11-2х)=0

Answer 1

1)x-(50-x)=12
x-50+x=12
2x=50+12
2x=62
x=62/2
x=21
2)x+(x+1)+(x+2)=9
x+x+1+x+2=9
3x=9-1-2
3x=6
x=6/3
x=2
3)21+(20-4x)-(11-2x)=0
21+20-4x-11+2x=0
30-2x=0
-2x=-30
2x=30
x=30/2
x=15