Mister Exam
Other calculators
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How to use it?
- Equation:
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Equation (25+x)-10=40
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Equation x^3+5*x^2-4*x-20=0
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Equation x^2+4*x=21
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Equation x^3+x-1=0
- Express {x} in terms of y where:
- 13*x+3*y=6
- -9*x+1*y=20
- 7*x-18*y=-4
- 5*x-13*y=-1
- Integral of d{x}:
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x^2+2x-4
- Graphing y =:
- x^2+2x-4
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Identical expressions
- x^ two +2x- four = zero
- x squared plus 2x minus 4 equally 0
- x to the power of two plus 2x minus four equally zero
- x2+2x-4=0
- x²+2x-4=0
- x to the power of 2+2x-4=0
- x^2+2x-4=O
-
Similar expressions
- x^2-2x-4=0
- x^2+2x+4=0
x^2+2x-4=0 equation
The teacher will be very surprised to see your correct solution 😉
The solution
Detail solution
This equation is of the form
A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
$$x_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$x_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = 1$$
$$b = 2$$
$$c = -4$$
, then
Because D > 0, then the equation has two roots.
or
$$x_{1} = -1 + \sqrt{5}$$
$$x_{2} = - \sqrt{5} - 1$$
a*x^2 + b*x + c = 0
A quadratic equation can be solved
using the discriminant.
The roots of the quadratic equation:
$$x_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$x_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = 1$$
$$b = 2$$
$$c = -4$$
, then
D = b^2 - 4 * a * c =
(2)^2 - 4 * (1) * (-4) = 20
Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
or
$$x_{1} = -1 + \sqrt{5}$$
$$x_{2} = - \sqrt{5} - 1$$
Vieta's Theorem
it is reduced quadratic equation
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = 2$$
$$q = \frac{c}{a}$$
$$q = -4$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = -2$$
$$x_{1} x_{2} = -4$$
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = 2$$
$$q = \frac{c}{a}$$
$$q = -4$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = -2$$
$$x_{1} x_{2} = -4$$
Rapid solution
[src]
___ x1 = -1 + \/ 5
$$x_{1} = -1 + \sqrt{5}$$
___ x2 = -1 - \/ 5
$$x_{2} = - \sqrt{5} - 1$$
x2 = -sqrt(5) - 1
Sum and product of roots
[src]
sum
___ ___ -1 + \/ 5 + -1 - \/ 5
$$\left(- \sqrt{5} - 1\right) + \left(-1 + \sqrt{5}\right)$$
=
-2
$$-2$$
product
/ ___\ / ___\ \-1 + \/ 5 /*\-1 - \/ 5 /
$$\left(-1 + \sqrt{5}\right) \left(- \sqrt{5} - 1\right)$$
=
-4
$$-4$$
-4
The graph