What is the distance between -48 and 17 on a number line

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

What expression is equivalent to 1/2(2+3x-6)

Find the missing dimension extra points