Help, needed with the following Math questions.

What is the point of inflection for the function f(x)=2cos4x on the interval (0, pi/2)

The candy store is having a 30% off sale. emma is going to buy $7.50 worth of candy. how much will she pay after the discount

Lines f and g are cut by the transversal d. the measure of 1 = 2x + 35 and the measure of 8 = 10x - 85. what value of x will show that lines f and g are parallel? a. 19 b. 26 c. 18 d. 15