Square root of 64 over 25

Evaluate cos2θ for cosθ = square root of 3/2

Asystem of equations has 1 solution.if 4x-y=5 is one of the equations , which could be the other equation ?

In order for the function to be linear, what must m be and why? m = 22 because the rate of change is 1. m = 20 because the rate of change is 3. m = 22 because the rate of change is -1. m = 20 because the rate of change is -3.