Mister Exam

Other calculators

f*(x)=-2*x-5 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]
f*x = -2*x - 5
$$f x = - 2 x - 5$$
Detail solution
Given the linear equation:
f*(x) = -2*x-5

Expand brackets in the left part
fx = -2*x-5

Move the summands with the unknown x
from the right part to the left part:
$$f x + 2 x = -5$$
Divide both parts of the equation by (2*x + f*x)/x
x = -5 / ((2*x + f*x)/x)

We get the answer: x = -5/(2 + f)
The solution of the parametric equation
Given the equation with a parameter:
$$f x = - 2 x - 5$$
Коэффициент при x равен
$$f + 2$$
then possible cases for f :
$$f < -2$$
$$f = -2$$
Consider all cases in more detail:
With
$$f < -2$$
the equation
$$5 - x = 0$$
its solution
$$x = 5$$
With
$$f = -2$$
the equation
$$5 = 0$$
its solution
no solutions
The graph
Rapid solution [src]
           5*(2 + re(f))             5*I*im(f)      
x1 = - --------------------- + ---------------------
                  2     2                 2     2   
       (2 + re(f))  + im (f)   (2 + re(f))  + im (f)
$$x_{1} = - \frac{5 \left(\operatorname{re}{\left(f\right)} + 2\right)}{\left(\operatorname{re}{\left(f\right)} + 2\right)^{2} + \left(\operatorname{im}{\left(f\right)}\right)^{2}} + \frac{5 i \operatorname{im}{\left(f\right)}}{\left(\operatorname{re}{\left(f\right)} + 2\right)^{2} + \left(\operatorname{im}{\left(f\right)}\right)^{2}}$$
x1 = -5*(re(f) + 2)/((re(f) + 2)^2 + im(f)^2) + 5*i*im(f)/((re(f) + 2)^2 + im(f)^2)
Sum and product of roots [src]
sum
      5*(2 + re(f))             5*I*im(f)      
- --------------------- + ---------------------
             2     2                 2     2   
  (2 + re(f))  + im (f)   (2 + re(f))  + im (f)
$$- \frac{5 \left(\operatorname{re}{\left(f\right)} + 2\right)}{\left(\operatorname{re}{\left(f\right)} + 2\right)^{2} + \left(\operatorname{im}{\left(f\right)}\right)^{2}} + \frac{5 i \operatorname{im}{\left(f\right)}}{\left(\operatorname{re}{\left(f\right)} + 2\right)^{2} + \left(\operatorname{im}{\left(f\right)}\right)^{2}}$$
=
      5*(2 + re(f))             5*I*im(f)      
- --------------------- + ---------------------
             2     2                 2     2   
  (2 + re(f))  + im (f)   (2 + re(f))  + im (f)
$$- \frac{5 \left(\operatorname{re}{\left(f\right)} + 2\right)}{\left(\operatorname{re}{\left(f\right)} + 2\right)^{2} + \left(\operatorname{im}{\left(f\right)}\right)^{2}} + \frac{5 i \operatorname{im}{\left(f\right)}}{\left(\operatorname{re}{\left(f\right)} + 2\right)^{2} + \left(\operatorname{im}{\left(f\right)}\right)^{2}}$$
product
      5*(2 + re(f))             5*I*im(f)      
- --------------------- + ---------------------
             2     2                 2     2   
  (2 + re(f))  + im (f)   (2 + re(f))  + im (f)
$$- \frac{5 \left(\operatorname{re}{\left(f\right)} + 2\right)}{\left(\operatorname{re}{\left(f\right)} + 2\right)^{2} + \left(\operatorname{im}{\left(f\right)}\right)^{2}} + \frac{5 i \operatorname{im}{\left(f\right)}}{\left(\operatorname{re}{\left(f\right)} + 2\right)^{2} + \left(\operatorname{im}{\left(f\right)}\right)^{2}}$$
=
5*(-2 - re(f) + I*im(f))
------------------------
            2     2     
 (2 + re(f))  + im (f)  
$$\frac{5 \left(- \operatorname{re}{\left(f\right)} + i \operatorname{im}{\left(f\right)} - 2\right)}{\left(\operatorname{re}{\left(f\right)} + 2\right)^{2} + \left(\operatorname{im}{\left(f\right)}\right)^{2}}$$
5*(-2 - re(f) + i*im(f))/((2 + re(f))^2 + im(f)^2)