Question

(7x + 5y = 12)
4x + = 18

Answer 1

Ответ:

(7х+5у=12

(4х+у=18

(7х+5(18-4х)=12

(у=18-4х

7х+90-20х=12

7х-20х=12-90

-13х=-78

х=6