Problema Solution
Find the formula for the parabola whose x-intercepts are at x=-3 and x=5 and the point (-5,60) is on the function's graph.
Answer provided by our tutors
We are given 3 points of the parabola:
(-3, 0), (5, 0) and (-5, 60)
The "general" form of a parabola's equation is:
y = ax^2 + bx + c, where a, b and c are constants
Plug the values that we have, (-3, 0), (5, 0) and (-5, 60, into the general equation:
a(-3)^2 + (-3)b + c = 0
a5^2 + 5b + c = 0
a(-5)^2 + (-5)b + c = 60
........
click here to see the system of equations solved for a, b and c
........
a = 3
b = -6
c = -45
The formula of the parabola is:
y = 3x^2 - 6x - 45