standard_description: Interpret products of whole numbers, e.g., interpret 5 × 7 as the total number of objects in 5 groups of 7 objects each. For example, describe a context in which a total number of objects can be expressed as 5 × 7.
problem_activity: Problem 1
A quadratic equation is shown below.
$${x^2=(2x-9)^2}$$
a.  Solve this equation by expanding and then factoring.
b.  Solve this equation by taking the square root of each side.
Problem 2
A physics teacher put a ball at the top of a ramp and let it roll down toward the floor. The class determined that the height of the ball could be represented by the equation
$${h=-16t^2+4}$$
, where the height,
$$h$$
, is measured in feet from the ground and time,
$$t$$
, is measured in seconds.
[IMG]
What do you notice about the structure of the quadratic expression in this problem?
In the equation, explain what the
$$4$$
represents.
Determine the time it takes for the ball to reach the floor. Interpret your solution(s) in context of the problem.


aligns: no