x^2+2x-3 equation
The teacher will be very surprised to see your correct solution 😉
The solution
Detail solution
This equation is of the form
a*x^2 + b*x + c = 0 A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
x 1 = D − b 2 a x_{1} = \frac{\sqrt{D} - b}{2 a} x 1 = 2 a D − b x 2 = − D − b 2 a x_{2} = \frac{- \sqrt{D} - b}{2 a} x 2 = 2 a − D − b where D = b^2 - 4*a*c - it is the discriminant.
Because
a = 1 a = 1 a = 1 b = 2 b = 2 b = 2 c = − 3 c = -3 c = − 3 , then
D = b^2 - 4 * a * c = (2)^2 - 4 * (1) * (-3) = 16 Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a) x2 = (-b - sqrt(D)) / (2*a) or
x 1 = 1 x_{1} = 1 x 1 = 1 Simplify x 2 = − 3 x_{2} = -3 x 2 = − 3 Simplify
Vieta's Theorem
it is reduced quadratic equation
p x + q + x 2 = 0 p x + q + x^{2} = 0 p x + q + x 2 = 0 where
p = b a p = \frac{b}{a} p = a b p = 2 p = 2 p = 2 q = c a q = \frac{c}{a} q = a c q = − 3 q = -3 q = − 3 Vieta Formulas
x 1 + x 2 = − p x_{1} + x_{2} = - p x 1 + x 2 = − p x 1 x 2 = q x_{1} x_{2} = q x 1 x 2 = q x 1 + x 2 = − 2 x_{1} + x_{2} = -2 x 1 + x 2 = − 2 x 1 x 2 = − 3 x_{1} x_{2} = -3 x 1 x 2 = − 3
Sum and product of roots
[src]
( − 3 + 0 ) + 1 \left(-3 + 0\right) + 1 ( − 3 + 0 ) + 1
1 ( − 3 ) 1 1 \left(-3\right) 1 1 ( − 3 ) 1