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If the roots of the equation x^2 − 16x − 612 = 0 are a and b, what is

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Bunuel
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If the roots of the equation x^2 − 16x − 612 = 0 are a and b, what is [#permalink] New post   28 Sep 2021, 03:15
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If the roots of the equation \(x^2−16x−612=0\) are a and b, what is the value of \(a+b\)?


A. -612

B. -16

C. 0

D. 16

E. 612
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D
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sumitkrocks
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Re: If the roots of the equation x^2 − 16x − 612 = 0 are a and b, what is [#permalink] New post   28 Sep 2021, 03:31
Sum of the roots of quadratic equation \(ax^2 + bx + c\)= 0 is \(\frac{-b}{a}\)
So answer is D

Bunuel wrote:
If the roots of the equation \(x^2−16x−612=0\) are a and b, what is the value of \(a+b\)?


A. -612

B. -16

C. 0

D. 16

E. 612
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Tejas10
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Re: If the roots of the equation x^2 − 16x − 612 = 0 are a and b, what is [#permalink] New post   28 Sep 2021, 09:05
The roots are -34 and plus 18.

So the answer is B.
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If the roots of the equation x^2 − 16x − 612 = 0 are a and b, what is [#permalink] New post   28 Sep 2021, 10:32
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In a quadratic equation of form \( ax^2 + bx + c = 0\) where R1 and R2 are the roots.

Sum of the roots = R1+ R2 =\( \frac{-b}{a}\) =\(\frac{ - coefficient of x}{coefficient of x^2}\)

Apply the same rule for sum of the roots in the quadratic equation below:

\( x^2 − 16x − 612 = 0\) where a and b are the roots.

Sum of the roots =a + b = \( \frac{- coefficient of x}{coefficient of x^2}\) =\( \frac{-(-16)}{1 }\)=\(16\)

Option D is the answer.
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If the roots of the equation x^2 − 16x − 612 = 0 are a and b, what is [#permalink]
28 Sep 2021, 10:32
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