The equation x2 – 1x – 90 = 0 has solutions {a, b}. What is a + b?
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 \(1\).
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*x2 = \(\frac ca\)
