How many acute angles does a decagon have

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

7x+8y=-18, 4x-9y=-3 solve the system of equations

5(-9w) put expression in distributive property