a) 
because it is equal to the area of the shaded region between X=4 and X=6, and the probability that X falls within some interval is given by the area under the PDF.
b) 
because the shaded region is a rectangle of height 1/5 (by virtue of X following a uniform distribution over the interval [2, 7], which has length 5).
Answer:
(y−2)29−x225=1
Step-by-step explanation:
Start with
Divide both sides by -3
If the absolute value of a number is 4, that number can either be 4 or -4: we have the two solutions
