Question

Solving System Of Equations by Elimination

1.) -14 = -20y - 7x
10y + 4 = 2x


2.) 3 + 2x - 7y = 10x
-3 - 7y = 10x

Answer 1

1). On the second equation I subtracted 10y from both sides. So I get:
-20y-7x=-14
-10y+2x=4
I then multiplied the 2nd equation by -2
-20y-7x=-14
20y-4x=-8
You combine like terms
-11x=-22
Divide both terms by -11
x=2
Then plug in x
-20y-7(2)=-14
-20y-14=-14
Add 14 on both sides
-20y=0
Divide both sides by -20
y=0
So in conclusion:
x=2 y=0

2). Add 7y in both equations so I get:
10x+7y=3
10x+7y=-3
So I multiply -1 on the top side.
-10x-7y=-3
10x+7y=3
Add like terms
0=0
No solution is the answer.