Given sinX= -12/13 and 270º < X < 360° what is the exact value of cos2X?

How do you use the additive inverse to evaluate an expression that uses subtraction in a full sentence

Create and solve a linear equation that represents the model, where squares and triangles are shown evenly balanced on a balance beam. assume the weight of a square is 1 unit and the weight of a triangle is unknown.

Which expression do you get when you eliminate the negative exponents of 4a^2 b^216a^-3 b