Evaluate the expression if h=120 and t=12.

Solve the system of equations. y= 2x y= x^2 - 15

Can someone me out here number 4 plz

Scores on a university exam are normally distributed with a mean of 78 and a standard deviation of 8. the professor teaching the class declares that a score of 70 or higher is required for a grade of at least “c.” using the 68-95-99.7 rule, what percentage of students failed to earn a grade of at least “c”?