Convert the following decimal into a rational number:
3.9

How do you multiply a mixed fraction by a regular fraction

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.)

Answer this question, only if you know the answer. 30 points and brainliest!