Question

For what values of a and b are the following equations both true?

a+2b=1
-3a-8b=1

Answer 1

multiply all terms in first equation by 4

+4a+8b = 4
-3a-8b = 1 now add
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1a+0b = 5 or a = 5
so use 5 for a in equation 1
5 + 2b = 1
2 b = -4
b = -2