Please help me! I don't understand related rates at all.

Fred bought 3 cd’s for $16.50 is this multiplication division subtraction or addition

Find the equation of the line that goes through the points (4, –1) and (2, –5). use slope formula,equation,to find the slope of a line that passes through the points. m = use slope-intercept form, y = mx + b, to find the y-intercept (b) of the line. b = write the equation in slope-intercept form, y = mx + b.

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