6. A young lad shoots off a model rocket. The height h, in meters, of the rocket off the ground is given by the formula h = -4.9t + 36.4t , where t is the time in seconds after the rocket is launched. Determine how long it takes for the rocket to reach a height of 20m. 7, When two times a number is subtracted from the square of the number, the result is 35. Determine the number(s) algebraically. 8. Helmut's rectangular emu pen measures 5m by 7m. When he increases both dimensions by the same amount, the area of the pen increases by 45m. Determine the dimensions of the larger pen