SOLUTION: Write the equation in standard form y = ax^2 + bx + c if the roots ar 3 and - 6 and it passes through (2, -8)
A. y = x^2 - 3x - 18
B. y = x^2 + 3x + 18
C. y = x^2 + 3x - 1
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-> SOLUTION: Write the equation in standard form y = ax^2 + bx + c if the roots ar 3 and - 6 and it passes through (2, -8)
A. y = x^2 - 3x - 18
B. y = x^2 + 3x + 18
C. y = x^2 + 3x - 1
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Question 1206304: Write the equation in standard form y = ax^2 + bx + c if the roots ar 3 and - 6 and it passes through (2, -8)
A. y = x^2 - 3x - 18
B. y = x^2 + 3x + 18
C. y = x^2 + 3x - 18
D. y = x^2 - 3x - 18 Found 2 solutions by greenestamps, MathLover1:Answer by greenestamps(13200) (Show Source):
The quadratic term in all 4 answer choices is x^2, which means the equation in standard form has a=1. Because of that, the given information that the graph passes through (2,-8) is not needed.
Solution method 1...
If the roots are 3 and -6, then the linear factors are (x-3) and (x-(-6))=(x+6). The equation is then y = (x-3)(x+6) = x^2+3x-18.
ANSWER: C
Solution method 2...
With a=1 in the standard form, Vieta's Theorem says the sum of the roots is -b and the product of the roots is c.
The sum of the roots is 3+(-6) = -3, so b is 3; the product of the roots is 3(-6) = -18, so c is -18: y = x^2+3x-18.
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Write the equation in standard form
if the roots are and and it passes through (,), use root product equation
...plug in all given values
so far we have
use root again
....eq.1
