Question

Solve following pairs of equations 1. 5m-5n=12;2m+9n=20

Answer 1

5m-5n=12 is eq1
2m+9n=20 is eq2
now eq1*2 and eq2*5
by solving
m= 208/55 and n=76/55

Answer 2

Given equations,

$5m - 5n=12\\2m+9n=20$

Multiplying the first eq, with 2 and the second eq, with 5, we get,

$10m - 10n=24\\\underline{10m+45n=100}\\\underline{\underline{-55n = -76}}\\\\=> \boxed{\boxed{\bold{n = \frac{76}{55}}}}$

Multiplying the first eq, with 9 and the second eq, with 5, we get,

$45m-45n=108\\\underline{10m+45n=100}\\\underline{\underline{55m = 208}}\\\\=> \boxed{\boxed{\bold{ m = \frac{208}{55}}}}$