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The equation x2 – 1x – 90 = 0 has solutions {a, b}. What is a + b?

 Mar 30, 2020

Best Answer 

 #2
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First you factor the equation into \((x-10)(x+9) = 0\).

So you're solutions are \(10\) and \(-9\). The sum of 10 and -9 is \(1\).

 Mar 30, 2020
 #1
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By vietas formulas:

a + b = -(-1)/1 = 1/1 = 1

 

Vietas formulas state:

Given a quadratic(it can be any polynomial, I'd recommend searching up vieta's formulas)

\(ax^2+bx+c = 0\)

and roots: x1, x2

 

x1 + x2 = \(\frac{-b}a\)

x1*x\(\frac ca\)

 Mar 30, 2020
edited by jfan17  Mar 30, 2020
 #2
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Best Answer

First you factor the equation into \((x-10)(x+9) = 0\).

So you're solutions are \(10\) and \(-9\). The sum of 10 and -9 is \(1\).

Guest Mar 30, 2020

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