How to solve this
Sin^4a - cos^4a

Adj has a total of 1075 dance and rock songs on her system. the dance selection is 4 times the size of the rock selection. write a system of equations to represent the situation.

Write an equation of the line that passes through 9,2 and is parallel to the line y=5/3x+9

Sally deposited money into a savings account paying 4% simple interest per year.the first year,she earn $75 in interest.how much interest will she earn during the following year?