SOLUTION: solve by using the best method for each system. 3x-3y=18 and x+y=3

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Question 27654: solve by using the best method for each system.
3x-3y=18 and
x+y=3
Answer by askmemath(368) About Me  (Show Source):
You can put this solution on YOUR website!
3x-3y=18
x+y=3
Multiplying the 2nd equation with 3
3x+3y = 9
Now, adding both
6x = 27
X+=+27%2F6
X = 4.5
Putting this value back into any equation we get Y = -1.5
Solved by pluggable solver: Linear System solver (using determinant)
Solve:
+system%28+%0D%0A++++3%5Cx+%2B+-3%5Cy+=+18%2C%0D%0A++++1%5Cx+%2B+1%5Cy+=+3+%29%0D%0A++

Any system of equations:


has solution

or



(x=4.5, y=-1.5}


Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
+system%28+%0D%0A++++3%5Cx+%2B+-3%5Cy+=+18%2C%0D%0A++++1%5Cx+%2B+1%5Cy+=+3+%29%0D%0A++We'll use substitution. After moving -3*y to the right, we get:
3%2Ax+=+18+-+-3%2Ay, or x+=+18%2F3+-+-3%2Ay%2F3. Substitute that
into another equation:
1%2A%2818%2F3+-+-3%2Ay%2F3%29+%2B+1%5Cy+=+3 and simplify: So, we know that y=-1.5. Since x+=+18%2F3+-+-3%2Ay%2F3, x=4.5.

Answer: system%28+x=4.5%2C+y=-1.5+%29.