2 what is the value of x given that pq || bc

Since PQ // BC, ABC and APQ are similar triangles, so we can use the Thales theoremAB / AP = AC / x   it means 9/3 = x + 20/ x   because  AB=6+3=93= x+20) /x   implies 3x = x +20, and 2x = 20, finally x= 20/2=10x= 10