Aclockwise rotation of 90° is equivalent to a counterclockwise rotation of how many degrees

The equation x2 – 1x – 90 = 0 has solutions {a, b}. what is a + b?

Rob spent 25%, percent more time on his research project than he had planned. he spent an extra h hours on the project. which of the following expressions could represent the number of hours rob actually spent on the project? two answers

The sides of a parallelogram are 24cm and 16cm. the distance between the 24cm sides is 8 cm. find the distance between the 16cm sides