Which of the following should be avoided when proving a trigonometric identity? Rewriting all expressions in terms of Sine and Cosine.
Factoring
Using a common denominator
Multiplying each side by the same value

This is part of my homework and I can't contact my teacher for it so I need some help

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

Amira is painting a rectangular banner 2 1/4 yards wide. the banner will have a blue background. amira has enough paint to cover 1 1/2 square yards of the wall. the school colors are blue and yellow, so amira wants to add yellow rectangles on the left and right sides of the blue rectangle. the yellow rectangles will each be 3/4 yards wide and the same height as the blue rectangle. what will be the total area of the two yellow rectangles?

What are the solutions of the equation x4 – 5x2 – 14 = 0? use factoring to solve. someone !