x - 3y = -9
-3y = -9 - x Multiply with -1
3y = 9 + x
4x + 3y= -6
4x + 9 + x = -6
5x + 9 = -6
5x = -6 - 9
5x = -15 Divide with 5
x= -15/5
x= -3
3y=9 + x
3y = 9 +(-3)
3y = 9 - 3
3y = 6 Divide with 3
y = 6/3
y= 2
Solution:
x = -3
y = 2
Solve: x-3y=-9
4x+3y=-6
2 answers
If we note that there is a +3y and a -3y in each of the equations, we simply add the two equations to get:
5x=-15, or x=-3
Substitute x=-3 in either one of the equations to get
-3-3y=-9
-3y=-6
y=2
5x=-15, or x=-3
Substitute x=-3 in either one of the equations to get
-3-3y=-9
-3y=-6
y=2
1 answer