What is the substitution of m=4n+11 and -6n+8m=36?

You are given m. Plug it in!

- 6n + 8(4n + 11) = 36

distribute

- 6n + 32n + 88 = 36

gather variable terms

26n + 88 = 36

subtract 88 from each side

26n = - 52

divide both sides integers by 26

n = - 2
------find m

m = 4(- 2) + 11

m = - 8 + 11

m = 3
------check

- 6(- 2) + 8(3) = 36

12 + 24 = 36

36 = 36
------checks