Question

2m - n = 15
2m + n = 3

Answer 1

if you want to do it using substitution only, then find 2m from first equation and substitute it in 2nd equation.

Answer 2

add the 2 equations .what do u get?

Answer 3

2m-n= 15 ------(1)
2m+n=3 ------(2)

Remove one variable first
as the constant before n is 1 and -1, we can cancel the two n by adding (1) and (2)
(1)+(2) : 4m=18 so m=9/2
Until this, there are two methods to continue our work.
Method 1:
sub n to any one of the equations.
For example, sub. m=9/2 into (1),
2(9/2) -n=15
n=-6

Method 2:
(1)-(2) to remove m.
-2n=12
n=-6

Answer 4

i think substitution needs to be used ...isn't it ?

Answer 5

Either way i still keep getting 4m = 18...

Answer 6

thats correct, so m=... ?

Answer 7

divide by 4 on both sides.

Answer 8

I don't know how to solve that one. /.\

Answer 9

why not??