Question

9x+y=580 x+9y=420 怎么解

Answer 1

9x+y=580 ①

x+9y=420 ②

①×9-②得

80x=580×9-420

80x=4800

x=4800÷80

x=60 代入 ①中得

540+y=580

y=40

x=60

y=40