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Write an equation for the quadratic graphed below

x-intercepts: (-2,0) and (3,0). y-intercept: (0,-2)

Write an equation for the quadratic graphed below x-intercepts: (-2,0) and (3,0). y-example-1
User RedX
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1 Answer

3 votes

Answer:

y = (1/3)(x +2)(x -3)

Explanation:

You want an equation for the quadratic whose graph has x-intercepts (-2, 0) and (3, 0), and y-intercept (0, -2).

X-intercepts

When a polynomial function has a zero at x=q, it means it has a factor of (x -q). Here, the zeros are given as x=-2 and x=3, so the function will have factors ...

(x -(-2)) = (x +2), and

(x -3)

Y-intercept

The y-intercept is the constant term in the product ...

y = a(x +2)(x -3) . . . . . . . product of factors of the quadratic

y = a(x² -x -6) = ax² -ax -6a

The constant term is -6a, and we want to choose the value of 'a' to make it be -2:

-6a = -2

a = -2/-6 = 1/3 . . . . . divide by the coefficient of 'a'

The equation can be written as ...

y = 1/3(x +2)(x -3)

User Nomnom
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