Giving 5 stars to the correct one

Subtract and simplify. (-y^2 – 4y - 8) – (-4y^2 – 6y + 3) show how you got the answer if your answer is right i will mark you

What is the domain of the step function f(x)=[2x]-1?

87.5% , 100% , 83.33 , 93.33% , 100% , 82.5% are all the academic points i've gotten this quarter. what's my final grade?