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40 votes
40 votes
I need help, Solve the system of equations x=-2y and x-y=9

User Candre
by
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1 Answer

15 votes
15 votes

Given

x = -2y

and

x - y = 9

Replace 2nd equation with the 1st:

x - y = 9

(-2y) - y = 9

-2y - y = 9

-3y = 9

y = 9/ -3

y = -3

So, now we know x = -2y, thus

x = -2(-3) = 6

So, the solution is:

(6,-3)

User Ben Carp
by
2.8k points