Explain what a value c in ratios?

Find the slope and the y-intercept if there's one and the equation of the line given these two points( 3, 2) and( 3, -4)

A50% increase followed by 33 1/2% decrease

Mario is constructing a frame for 10 in. by 8 in. photo. he wants the frame to be the same with all the way around in the same area of the frame and photo to be 120 square inches what is the dimension of the frame?