Question

How do u solve this question using elimination m - n = -9 & 7m + 2n = 9? Please help me!!!

Answer 1

m - n = -9 -->(2)
7m + 2n = 9
-----------------
2m - 2n = -18 (result of multiplying by 2)
7m + 2n = 9
-----------------add
9m = -9
m = -1

now sub -1 in for m in either of the original equations
m - n = -9
-1 - n = -9
-n = -9 + 1
-n = -8
n = 8

check...
7m + 2n = 9
7(-1) + 2(8) = 9
-7 + 16 = 9
9 = 9 (correct)

m = -1 and n = 8

any questions ?

Answer 2

No and thanx :)

Answer 3

YW :)