What is the gcf of 90 and 15

There is a line with slope 1/a going through the point (a, a²). find the equation of the line perpendicular to this line at this point. (don’t let this problem intimidate you! solve the problem as you would if i’d given you specific values. just use variables instead.)

Find the midpoint m of z1=(8+5i) and z2=(12+3i)

Maria walks a round trip of 0.75 mile to school every day.how many miles will she walk in 4.5 days