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

Algebra ->  Algebra  -> Coordinate Systems and Linear Equations -> SOLUTION: solve by elimination method 9x-9y=9 7y-3x=-5      Log On

Ad: You enter your algebra equation or inequality - Algebrator solves it step-by-step while providing clear explanations. Free on-line demo .
Ad: Algebra Solved!™: algebra software solves algebra homework problems with step-by-step help!
Ad: Algebrator™ solves your algebra problems and provides step-by-step explanations!

   

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: Error: 'Can't call method "invoke_solver" on an undefined value at /home/ichudov/project_locations/algebra.com/templates/Algebra/Solver/PerlSolver.pm line 115. Can't call method "invoke_solver" on an undefined value at /home/ichudov/project_locations/algebra.com/templates/Algebra/Solver/PerlSolver.pm line 115. '. Can't call method "invoke_solver" on an undefined value at /home/ichudov/project_locations/algebra.com/templates/Algebra/Solver/PerlSolver.pm line 115. Can't call method "invoke_solver" on an undefined value at /home/ichudov/project_locations/algebra.com/templates/Algebra/Solver/PerlSolver.pm line 115.
error_location: 101



Same result as before...

I hope the above steps were helpful.

For FREE Step-By-Step videos in Introduction to Algebra, please visit http://www.FreedomUniversity.TV/courses/IntroAlgebra and for Trigonometry visit http://www.FreedomUniversity.TV/courses/Trigonometry.

Good luck in your studies!

Respectfully,
Dr J