Can someone please help me with math. Pls don't take my points.

1. during first 10 seconds 2. between 10 seconds and 35 seconds 3. during 35 seconds to 40 seconds

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

Write an algebraic expression to match each statement a. four less than 8 times a number b. twice the difference of a number and six c. nine from a number squared