How many liters of a 10% alcohol solution must be mixed with 90 liters of a 40% solution
to get a 20% solution?

If square root x = -7, then x= -49 true or false

After t seconds, a ball tossed in the air from the ground level reaches a height of h feet given by the equation h = 144t-16t^2. after how many seconds will the ball hit the ground before rebounding?

The rectangle shown has a perimeter of 108 cm and the given area. its length is 6 more than five times its width. write and solve a system of equations to find the dimensions of the rectangle.