What expression is equivalent to 4x/5-2x/3

Acamper leaves camp on a kayak and travels 50 miles east on a river, then he ties his kayak to the bank and travels 20 miles north on a bicycle. this trip can be plotted on the coordinate plane, where the camp is the point (0, 0). the distant of the camper to the camp can be found using the distance formula. which other formula can he use? a) 502 - 202 b) 502 + 202 c) 502 - 202 d) 502 + 202

Question and answers are in the attached picture. you so much in advance.

If the scale factor between two circles is 2x/5y what is the ratio of their areas?