Help me solve this algebra question.

Use the elimination method to find the solution to the system of equations. 2x - 3y = -9 -x + 3y = 6

There are 20 children in the cast of a class play and 8 of the children are boys of the boys 4 have a speaking part in the play and of the girls 8 do not have a speaking part in the play if a child from the cast of the place chosen at random what is the probability that the child has a speaking part

The last time i bought this product , it cost $20.00 but it looks like it cost 29. 60 today? what is the increase