{2x+3y=-9,5x-y=3用代入法

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{2x+3y=-9,5x-y=3用代入法{2x+3y=-9,5x-y=3用代入法{2x+3y=-9,5x-y=3用代入法{2x+3y=-9①5x-y=3②由②得:y=5x-3③将③代入①:2x+3(5

{2x+3y=-9,5x-y=3用代入法
{2x+3y=-9,5x-y=3用代入法

{2x+3y=-9,5x-y=3用代入法
{2x+3y=-9①
5x-y=3②
由②得:
y=5x-3③
将③代入①:
2x+3(5x-3)=-9
2x+15x-9=-9
17x=0
x=0
y=5*0-3=-3

{2x+3y=-9 (1)
5x-y=3
y=5x-3
将y=5x-3代入(1)
2x+3(5x-3)=-9
2x+15x-9=-9
x=0
y=-3