18) slope and y-intercept, I need help ASAP

What is the value of x in the this question ?

An isosceles trapezoid with a perimeter of 42 inches. each of the congruent non parallel sides is 5 inches long, and the trapezoid is 3 inches tall. how long are the two parallel sides? a. 10 in, 22 in b. 16 in, 16 in c. 10 in, 16 in d. 12 in, 20 in

Andy wants to find the distance d across a river. he located points as shown in the figure, then use similar triangles to find that d = 223.5 feet. how can you tell without calculating that he must be wrong? tell what you think he did wrong and correct his error. round your answer to the nearest tenth if necessary. andy must have used the wrong . the distance d is actually feet.