Question

If 3m – 5n = – 1 and 2m = n – 3, find the values of (3m + 5n) and (m + 2n).​

Answer 1

Solution

3m-5n+1 = 0. (1)

2m- n+3 = 0. (2)

(1) multiply by 2. 6m-10n+2 = 0

(2) multiply by 3. 6m- 3n+9 = 0

-7n-7 = 0

n = -1

substitute in (1),

3m-5(-1)+1 = 0.

3m = -6

m = -2

3m + 5n = 3(-2)+5(-1) = -6-5 = -11

m+2n = -2+2(-1) = -2-2 = -4