How do you solve $5m+n=43$ and $m-2n=13$ using substitution?

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Answer 1 · 2018-04-03T22:18:22

$m = 9$
$n=-2$

$5m + n = 43 => n = 43-5m$

$m-2(43-5m )=13$
$m-86+10m =13$
$11m-86=13$
$11m=99$

$m=99/11=9$

$n = 43-5m$
$n = 43-5 times 9 =-2$

Double check:

$5 times 9 + (- 2) = 43$
$9-2times(-2)=9+4 = 13$

How do you solve 5m+n=435m+n=43 and m-2n=13m-2n=13 using substitution?