Question 747082: Solve the system of equations: 3x - y = 9 and 6x + y = 0
Answer by lenny460(1073)   (Show Source):
You can put this solution on YOUR website! Solve the system of equations: 3x - y = 9 and 6x + y = 0
We can solve the above using the Addition Method:
3x - y = 9
6x + y = 0
Add the above two equations together:
3x - y + 6x + y = 9 + 0
Combine like terms:
3x + 6x = 9x
-y + y = 0
9 + 0 = 9
We now have:
9x = 9
x = 1
Substitute x = 1 into the first equation 3x - y = 9
3(1) - y = 9
3 - y = 9
Subtract 3 from each side of the equation.
3 - y - 3 = 9 - 3
Combine like terms:
3 - 3 = 0
9 - 3 = 6
-y = 6
Divide each side by -1
-1y/-1 = 6/-1
y = -6
Plug the x and y values into equation 2 to check:
6x + y = 0
6(1) + (-6) = 0
6 + (-6) = 0
Answer:
x = 1 and
y = -6
Lennox Obuong
Algebra Tutor
Nairobi, Kenya
Email: obuong3@aol.com
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