How do you solve $5m - 4n = 11$ and $3m = n + 15$ using substitution?

Question

2402 views around the world

You can reuse this answer
Creative Commons License

Answer 1 · 2018-05-01T11:00:38

$m = 7$

$n = 6$

$5m - 4n = 11$ ⇒ EQN 1

$3m = n + 15$ ⇒ EQN 2

$3m - 15 = n$ ⇒EQN 3

Substitute EQN 3 into EQN 1

⇒ $5m - 4*(3m-15) = 11$

⇒ $5m - 12m + 60 = 11$

⇒ $-7m = -49$

⇒ $m = 7$

When $m=7$ ,

⇒ $3(7) = n + 15$

⇒ $n = 6$

Check if the answers are correctly calculated.

$5(7) - 4(6) = 11$ √

$3(7) = 6 + 15$ √

How do you solve 5m - 4n = 115m - 4n = 11 and 3m = n + 153m = n + 15 using substitution?