You basically dilate the slope of y to the slope of x by the same scale factor at which all the sides of the triangles are dilated or increased/decreased by.
Subtract 9 from both sides
b = -12 - 9
simplify -12 - 9
Answer: b = -21
9 + -21 = -12 is true.
simplify brackets
simplify q + -9 to q - 9
add 9 to both sides
simplify 12 + 9 to 21
q = 21
21 + -9 = 12 is true.
You simply divide 32 ÷ 4 = 8, for problem A
First we need to count the total number scores. This can be done from the stem and leaf plot. The total number of scores are 19. The total number of values is odd, so the median position will be:

Thus the 10th score is the median score for the class of Mr. Robert. The 10th score from the stem and leaf plot is 81.
Thus 81 is the median score of Mr. Robert's Class.