解一个二元一次方程~x-3y=5{ 2x+y=5要解题过程,thanks!
2019-04-02
解一个二元一次方程~
x-3y=5
{
2x+y=5
要解题过程,thanks!
优质解答
x-3y=5.(1)
2x+y=5.(2)
From (1)
x=5+3y.(3)
Put (3) into (2)
2(5+3y)+y=5
10+6y+y=5
7y=-5
y=-5/7.(4)
Put (4)into (3)
x=5+3(-5/7)
x=5-(15/7)
x=-20/7
So,x=-20/7 ,y=-5/7
x-3y=5.(1)
2x+y=5.(2)
From (1)
x=5+3y.(3)
Put (3) into (2)
2(5+3y)+y=5
10+6y+y=5
7y=-5
y=-5/7.(4)
Put (4)into (3)
x=5+3(-5/7)
x=5-(15/7)
x=-20/7
So,x=-20/7 ,y=-5/7