Linear functions please help

look a the sides they are perpendicular

ca = ec

cpctc makes it so that corresponding parts of the triangle you proved to be equal are equal, the other options aren't part of the part of the triangles you proved to be equal.

first the equation needs to be simplified. so the equation would now look like:   52-24+11

then you multiply.

and when you multiply, you will get the answer of 39.