SOLUTION: Use the method of substitution to solve the system of linear equations a) x-y=8 x-y=-2 b) 2x+y=5 4x-3y=15

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Question 115826: Use the method of substitution to solve the system of linear equations
a) x-y=8
x-y=-2
b) 2x+y=5
4x-3y=15
Answer by MathLover1(20850) About Me  (Show Source):
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a)
x-y=8
x-y=-2

Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
+system%28+%0D%0A++++1%5Cx+%2B+-1%5Cy+=+8%2C%0D%0A++++1%5Cx+%2B+-1%5Cy+=+-2+%29%0D%0A++We'll use substitution. After moving -1*y to the right, we get:
1%2Ax+=+8+-+-1%2Ay, or x+=+8%2F1+-+-1%2Ay%2F1. Substitute that
into another equation:
1%2A%288%2F1+-+-1%2Ay%2F1%29+%2B+-1%5Cy+=+-2 and simplify: So, we know that y=10=0. Since x+=+8%2F1+-+-1%2Ay%2F1, x=18.

Answer: system%28+x=18%2C+y=10=0+%29.



b)
2x%2By=5
4x-3y=15
Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
+system%28+%0D%0A++++2%5Cx+%2B+1%5Cy+=+5%2C%0D%0A++++4%5Cx+%2B+-3%5Cy+=+15+%29%0D%0A++We'll use substitution. After moving 1*y to the right, we get:
2%2Ax+=+5+-+1%2Ay, or x+=+5%2F2+-+1%2Ay%2F2. Substitute that
into another equation:
4%2A%285%2F2+-+1%2Ay%2F2%29+%2B+-3%5Cy+=+15 and simplify: So, we know that y=-1. Since x+=+5%2F2+-+1%2Ay%2F2, x=3.

Answer: system%28+x=3%2C+y=-1+%29.