Mister Exam

Other calculators

(-x-5)(2x+4)=0

(-x-5)(2x+4)=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] 
(-x - 5)*(2*x + 4) = 0
(−x−5)(2x+4)=0\left(- x - 5\right) \left(2 x + 4\right) = 0
Simplify
Detail solution
Expand the expression in the equation
(−x−5)(2x+4)=0\left(- x - 5\right) \left(2 x + 4\right) = 0
We get the quadratic equation
−2x2−14x−20=0- 2 x^{2} - 14 x - 20 = 0
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:
x1=D−b2ax_{1} = \frac{\sqrt{D} - b}{2 a}
x2=−D−b2ax_{2} = \frac{- \sqrt{D} - b}{2 a}
where D = b^2 - 4*a*c - it is the discriminant.
Because
a=−2a = -2
b=−14b = -14
c=−20c = -20
, then
D = b^2 - 4 * a * c = 

(-14)^2 - 4 * (-2) * (-20) = 36

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

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

or
x1=−5x_{1} = -5
x2=−2x_{2} = -2
The graph
05-20-15-10-510-500250
Plot the graph f1(x)
Plot the graph f2(x)
Sum and product of roots [src] 
sum
-5 - 2
−5−2-5 - 2 
=
-7
−7-7 
product
-5*(-2)
−−10- -10 
=
10
1010 
10
Rapid solution [src] 
x1 = -5
x1=−5x_{1} = -5 
x2 = -2
x2=−2x_{2} = -2 
x2 = -2
Numerical answer [src] 
x1 = -2.0
x2 = -5.0
x2 = -5.0
The graph
(-x-5)(2x+4)=0 equation
    © Mister Exam – Calculator