a sales associate in a department store earns a commission on each suit and a pair of shoes sold. one week, she earned $47 in commission for selling 3 suits and a pair of shoes. the next week, she earned $107 in commission for selling 7 suits and 2 pairs of shoes. how much commission does she earn for selling each suit and each pair of shoes? solve by substitution.

For this one you have to make the equations. And what I like to do is write it out, like this.
One Week- $47
3 suits 
1 shoes (pairs)

Another Week- $107
7 suits 
2 shoes (pairs)

Then I make/choose my variables.
For suits, it's going to be s.
And For shoes let's do p.
(Or if you would like better you can do x and y, which ever works best for you)

Now for the equations:
One Week,   47= 3s +1p
Another Week,   107= 7s + 2p

Now it's time for the Substitution! :) Your last problem had it easier because it was already in the form, y=mx+b, but since ours aren't we have to change it to y=mx+b.

One Week,  -0.33p + 15.67 =s 
Another Week,  -0.29p + 15.29 =s

Now you can use substitution. :)
For p i got 9.5 or 9.50.
For s, i got 12.34

So the answer is (9.5,12.34) or (12.34, 9.5) I forgot which sorry.
The work is in the picture(s).
I hoped this helped. :)