Question

solve 3x-y=0 x-y+6=0

Answer 1

3x-y=0. ------(1)eqⁿ

x-y+6=0
=x-y=-6. -------(2)eqⁿ

(1)eqⁿ-3×(2)eqⁿ

3x-y=0
-(3x-3y=-18)
__________
2y=18

y=18/2=9
put this value in eqⁿ 1

3x-y=0
3x-9=0
3x=9
x=3

so x=3 y=9

Answer 2

3x-y=0 and x+y+6=0
3x-y=0 x+y=-6
now by elimination method.
3x-y=0
x+y=-6
4x=-6
x=-6/4
x=-3/2
putting value of x in eq 1 we get
3×-3/2-y=0
9-2y=0
-2y=-9
y=9/2