Answer:
x=-1, y=4
Explanation:
When we solve by elimination, we are getting rid of one variable, in this case y. We will add the two equations together.
5x-4y=-21
-2x+4y=18
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3x = -3
Divide each side by 3
3x/3 =-3/3
x =-1
Now we need to calculate y
-2x +4y = 18
Substitute x=-1
-2(-1)+4y = 18
2+4y =18
Subtract 2 from each side
4y = 18-2
4y=16
Divide each side by 4
4y=16/4
y =4