Mister Exam

Other calculators

x^2-(10/3)*x-1=0 equation

The teacher will be very surprised to see your correct solution 😉

v

Numerical solution:

Do search numerical solution at [, ]

The solution

You have entered [src]
 2   10*x        
x  - ---- - 1 = 0
      3          
$$\left(x^{2} - \frac{10 x}{3}\right) - 1 = 0$$
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:
$$x_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$x_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = 1$$
$$b = - \frac{10}{3}$$
$$c = -1$$
, then
D = b^2 - 4 * a * c = 

(-10/3)^2 - 4 * (1) * (-1) = 136/9

Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a)

x2 = (-b - sqrt(D)) / (2*a)

or
$$x_{1} = \frac{5}{3} + \frac{\sqrt{34}}{3}$$
$$x_{2} = \frac{5}{3} - \frac{\sqrt{34}}{3}$$
Vieta's Theorem
it is reduced quadratic equation
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = - \frac{10}{3}$$
$$q = \frac{c}{a}$$
$$q = -1$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = \frac{10}{3}$$
$$x_{1} x_{2} = -1$$
The graph
Rapid solution [src]
           ____
     5   \/ 34 
x1 = - - ------
     3     3   
$$x_{1} = \frac{5}{3} - \frac{\sqrt{34}}{3}$$
           ____
     5   \/ 34 
x2 = - + ------
     3     3   
$$x_{2} = \frac{5}{3} + \frac{\sqrt{34}}{3}$$
x2 = 5/3 + sqrt(34)/3
Sum and product of roots [src]
sum
      ____         ____
5   \/ 34    5   \/ 34 
- - ------ + - + ------
3     3      3     3   
$$\left(\frac{5}{3} - \frac{\sqrt{34}}{3}\right) + \left(\frac{5}{3} + \frac{\sqrt{34}}{3}\right)$$
=
10/3
$$\frac{10}{3}$$
product
/      ____\ /      ____\
|5   \/ 34 | |5   \/ 34 |
|- - ------|*|- + ------|
\3     3   / \3     3   /
$$\left(\frac{5}{3} - \frac{\sqrt{34}}{3}\right) \left(\frac{5}{3} + \frac{\sqrt{34}}{3}\right)$$
=
-1
$$-1$$
-1
Numerical answer [src]
x1 = 3.61031729828177
x2 = -0.276983964948433
x2 = -0.276983964948433