SOLUTION: solve by elimination method 9x-9y=9 7y-3x=-5

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Question 214870: solve by elimination method
9x-9y=9
7y-3x=-5
Answer by drj(1380) About Me  (Show Source):
You can put this solution on YOUR website!
Solve by elimination method
9x-9y=9 Equation A
7y-3x=-5 Equation B

Step 1. Multiply Equation by 3 and add to equation A

9x-9y=9 Equation A
-9x%2B21y=-15 Equation B-1 after multiplying by 3
Adding above equations yield,
-9y%2B21y=9%2B%28-15%29
12y=-6
y=-6%2F12=-1%2F2
Step 2. Substitute y=-1/2 into one of the equations say Equation A

9x-9y=9 Equation A

9x-9%28-1%2F2%29=9

x%2B1%2F2=1

x=1%2F2

Step 3. Solution is (1/2,-1/2) or x=1%2F2 and y=-1%2F2

As a check, let's solve by elimination

Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
+system%28+%0D%0A++++9%5Cx+%2B+-9%5Cy+=+9%2C%0D%0A++++-3%5Cx+%2B+7%5Cy+=+-5+%29%0D%0A++We'll use substitution. After moving -9*y to the right, we get:
9%2Ax+=+9+-+-9%2Ay, or x+=+9%2F9+-+-9%2Ay%2F9. Substitute that
into another equation:
-3%2A%289%2F9+-+-9%2Ay%2F9%29+%2B+7%5Cy+=+-5 and simplify: So, we know that y=-0.5. Since x+=+9%2F9+-+-9%2Ay%2F9, x=0.5.

Answer: system%28+x=0.5%2C+y=-0.5+%29.



Same result as before...

I hope the above steps were helpful.

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Good luck in your studies!

Respectfully,
Dr J