Final answer:
The value of 'a' in the parabolic equation y = a(x - 15)^2 + 18, when the parabola goes through the point (2, 7), is calculated by substitution and determined to be -11/169.
Step-by-step explanation:
The question involves finding the value of 'a' in the quadratic equation of a parabola representing the trajectory of a tossed donut: y = a(x - 15)^2 + 18, given that the parabola goes through the point (2, 7). To solve for 'a', we substitute the given point into the equation.
Substituting x = 2 and y = 7, we get:
7 = a(2 - 15)^2 + 18
Now, let's proceed with the calculation:
7 = a(-13)^2 + 18
7 = 169a + 18
Subtracting 18 from both sides:
-11 = 169a
Dividing by 169 to solve for 'a':
a = -11/169
Therefore, the constant 'a' in the equation of the parabola is -11/169.