How to estimate the square root of 32

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

Which answer is the solution set to the inequality |x|< 9? a. x< -9 or x> 9 b. x> -9 and x< 9 c. x> -9 or x< 9 d. x< 9 and x< 9

Suppose that sahil knows that 45 people with ages of 18 to 29 voted. without using a calculator, he quickly says then 135 people with ages of 30to 49 voted. is he correct? how might sohil have come up with his answer so quickly?