Question

Решите уравнения
а) 9х-72=909
б) 21-(5х-11)=12

Answer 1

9х-72=909
9х=909+72
9х=981
х=981:9
х=109


21-(5х-11)=12
5х-11=21-12
5х-11=9
5х=9+11
5х=20
х=20:5
х=4

Answer 2

ок

Answer 3

9х-72=909. 9х=909+72. 9х=981. х=981÷9. х=109; 21-(5х-11)=12. 21-5х+11=12. 32-5х=12. -5х=12-32. -5х=-20. х=-4.