172k views
4 votes
10x + 7y = -3
5x - y = 3

User Wilda
by
6.9k points

1 Answer

4 votes
If this is a system of equations then:
Multiply 5x-y=3 by -2
=> -10x+2y=-6
Now you sum the equations:
10x-10x+7y+2y=-3-6
=> 9y=-9
Then just divide by 9: y=-1
Now to get x, choose one of the equations and use the value we got from y:
5x-(-1)=3 => 5x+1=3 => 5x=3-1
=> 5x=2
=> x=2/5

(x,y)=(2/5, -1)
User Johannes Thoma
by
7.4k points