Question

solve by the substitution method
2m+n=5
m-9n=12???

Answer 1

n=5-2m

plug "5-2m" into the 2nd equation instead of "n" (substitution):
m-9(5-2m)=12

find m from above, then find n from the first equation (using the m you found).

Answer 2

does that make sense nikkiem1 ?

Answer 3

2m+n=5
n=5-2m
m-9n=12
m-9(5-2m)=12
m-45+18m=12
m+18m=57
19m=57
m=3

Answer 4

do i have to collect like terms?

Answer 5

as you see above in Kush's steps - collection of like terms is being done.

Answer 6

For example: these steps are exactly that - collection of like terms:

m-45+18m=12
m+18m=57
19m=57

Answer 7

now that you know that
m=3

can you find
n=?