Mister Exam
Other calculators
-
How to use it?
- Equation:
-
Equation -7x=4
-
Equation x^2-6=0
- Equation x^2-x-90=0
-
Equation x^2+7*x+12=0
- Express {x} in terms of y where:
- -6*x-11*y=-20
- -15*x+7*y=1
- -1*x-20*y=1
- -1*x-15*y=13
- Factor squared:
- x^2-2*x+8
- Graphing y =:
- x^2-2*x+8
- Factor polynomial:
- x^2-2*x+8
-
Identical expressions
- x^ two - two *x+ eight = zero
- x squared minus 2 multiply by x plus 8 equally 0
- x to the power of two minus two multiply by x plus eight equally zero
- x2-2*x+8=0
- x²-2*x+8=0
- x to the power of 2-2*x+8=0
- x^2-2x+8=0
- x2-2x+8=0
- x^2-2*x+8=O
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Similar expressions
- x^2-2*x-8=0
- x^2+2*x+8=0
x^2-2*x+8=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
$$a = 1$$
$$b = -2$$
$$c = 8$$
, then
Because D<0, then the equation
has no real roots,
but complex roots is exists.
or
$$x_{1} = 1 + \sqrt{7} i$$
$$x_{2} = 1 - \sqrt{7} i$$
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
$$a = 1$$
$$b = -2$$
$$c = 8$$
, then
D = b^2 - 4 * a * c =
(-2)^2 - 4 * (1) * (8) = -28
Because D<0, then the equation
has no real roots,
but complex roots is exists.
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
or
$$x_{1} = 1 + \sqrt{7} i$$
$$x_{2} = 1 - \sqrt{7} i$$
Vieta's Theorem
it is reduced quadratic equation
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = -2$$
$$q = \frac{c}{a}$$
$$q = 8$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = 2$$
$$x_{1} x_{2} = 8$$
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = -2$$
$$q = \frac{c}{a}$$
$$q = 8$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = 2$$
$$x_{1} x_{2} = 8$$
Sum and product of roots
[src]
sum
___ ___ 1 - I*\/ 7 + 1 + I*\/ 7
$$\left(1 - \sqrt{7} i\right) + \left(1 + \sqrt{7} i\right)$$
=
2
$$2$$
product
/ ___\ / ___\ \1 - I*\/ 7 /*\1 + I*\/ 7 /
$$\left(1 - \sqrt{7} i\right) \left(1 + \sqrt{7} i\right)$$
=
8
$$8$$
8
Rapid solution
[src]
___ x1 = 1 - I*\/ 7
$$x_{1} = 1 - \sqrt{7} i$$
___ x2 = 1 + I*\/ 7
$$x_{2} = 1 + \sqrt{7} i$$
x2 = 1 + sqrt(7)*i
Numerical answer
[src]
x1 = 1.0 - 2.64575131106459*i
x2 = 1.0 + 2.64575131106459*i
x2 = 1.0 + 2.64575131106459*i
The graph