Question

3m + n =7
m + 2n = 9​

Answer 1

n = 4, m = 1

Explanation:

Given the 2 equations

3m + n = 7 → (1)

m + 2n = 9 → (2)

Rearrange (2) expressing m in terms of n, by subtracting 2n from both sides

m = 9 - 2n → (3)

Substitute m = 9 - 2n into (1)

3(9 - 2n) + n = 7 ← distribute left side

27 - 6n + n = 7 ← simplify left side

27 - 5n = 7 ( subtract 27 from both sides )

- 5n = - 20 ( divide both sides by - 5 )

n = 4

Substitute n = 4 into (3) for corresponding value of m

m = 9 - (2 × 4) = 9 - 8 = 1

Thus m = 1 and n = 4