How do you solve $7m+n=41$ and $m-9n=45$ using substitution?

Question

1214 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2016-05-16T20:22:45

$n=-137/32$
$m=1449/224$

$7m+n=41$

$color(green)(7m)=41-n" (1)"$

$m-9n=45" let's extend both side of equation by 7"$

$color(red)(7)*m-color(red)(7)*9n=color(red)(7)*45$

$color(green)(7m)-63n=315$

$41-n-63n=315$

$41-64n=315$

$-64n=315-41$

$-64n=274$

$n=-274/64=-137/32$

$"use (1)"$

$7m=41+137/32$

$7m=(1312+137)/32$

$7m=1449/32$

$m=(1449)/(32*7)$

$m=1449/224$

How do you solve 7m+n=417m+n=41 and m-9n=45m-9n=45 using substitution?