Idont the know the answer to c-d=b for c

In triangle opq right angled at p op=7cm,oq-pq=1 determine the values of sinq and cosq

Δabc is dilated by a scale factor of 3 with the origin as the center of dilation to form δa′b′c′. the slope of is -1.2. the length of is p units, the length of is q units, and the length of is r units. the slope of is . the length of is units.

Having a hard time understanding this question (see attachment).