Final answer:
The question involves solving for time 't' when a rocket reaches a certain height as described by a quadratic equation. There appears to be a typo in the equation given, but it is typically solved through algebraic manipulation. An accurate solution requires correcting the provided equation first.
Step-by-step explanation:
The question at hand involves determining the time when the height of a rocket follows a specific equation and is at a certain value. The equation for the rocket's height provided, h = -490t² + 1120t², seems to contain a typo, as it has the term t² twice with different coefficients. Correcting the typo and using a typical format for quadratic equations, we should have the equation in the form of h = at² + bt + c, where 'h' represents the height and 't' represents the time. Assuming the corrected equation is h = (1120 - 490)t², we can then find the height for a given time.
To find when the height is 640 centimeters, we would set up the equation 640 = (1120 - 490)t² and solve for 't'. The solution will involve basic algebraic manipulation and solving a quadratic equation. Using this method, we would factor the quadratic equation and find the possible values of 't' that satisfy the height of 640 centimeters. However, without the proper equation, solving for the time 't' accurately is not possible.