SOLUTION: The sum of two numbers is 172. The first is 8 less than 5 times the second. Find the first number. Please help me I don't understand how to solve this.

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Question 1050186: The sum of two numbers is 172. The first is 8 less than 5 times the second. Find the first number. Please help me I don't understand how to solve this.

Answer by advanced_Learner(501) About Me  (Show Source):
You can put this solution on YOUR website!
a+b=172
a=-8+5b
Solved by pluggable solver: SOLVE linear system by SUBSTITUTION
Solve:
+system%28+%0D%0A++++1%5Ca+%2B+1%5Cb+=+172%2C%0D%0A++++1%5Ca+%2B+-5%5Cb+=+-8+%29%0D%0A++We'll use substitution. After moving 1*b to the right, we get:
1%2Aa+=+172+-+1%2Ab, or a+=+172%2F1+-+1%2Ab%2F1. Substitute that
into another equation:
1%2A%28172%2F1+-+1%2Ab%2F1%29+%2B+-5%5Cb+=+-8 and simplify: So, we know that b=30. Since a+=+172%2F1+-+1%2Ab%2F1, a=142.

Answer: system%28+a=142%2C+b=30+%29.