Mister Exam
Other calculators
-
How to use it?
- Equation:
-
Equation (-x-5)(2x+4)=0
-
Equation 5(x+1)(x-3)=4x^2-8x
-
Equation 16+6x=5(1-2x)-13
- Equation (x-3)/(x+5)+7=80/(x²-25)
- Express {x} in terms of y where:
- 9*x+18*y=6
- 15*x-15*y=16
- sqrt(x^2+y^2+4x-6y-12)+(x^2+10x-27)=8-|y-9|+|y-3|
- (x^2+y^2-1)^3+x^2*y^3=0
-
Identical expressions
- (-x- five)(2x+ four)= zero
- ( minus x minus 5)(2x plus 4) equally 0
- ( minus x minus five)(2x plus four) equally zero
- -x-52x+4=0
- (-x-5)(2x+4)=O
-
Similar expressions
- (-x+5)(2x+4)=0
- (x-5)(2x+4)=0
- (-x-5)(2x-4)=0
(-x-5)(2x+4)=0 equation
The teacher will be very surprised to see your correct solution 😉
The solution
Detail solution
Expand the expression in the equation
$$\left(- x - 5\right) \left(2 x + 4\right) = 0$$
We get the quadratic equation
$$- 2 x^{2} - 14 x - 20 = 0$$
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
$$a = -2$$
$$b = -14$$
$$c = -20$$
, then
Because D > 0, then the equation has two roots.
or
$$x_{1} = -5$$
$$x_{2} = -2$$
$$\left(- x - 5\right) \left(2 x + 4\right) = 0$$
We get the quadratic equation
$$- 2 x^{2} - 14 x - 20 = 0$$
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:
$$x_{1} = \frac{\sqrt{D} - b}{2 a}$$
$$x_{2} = \frac{- \sqrt{D} - b}{2 a}$$
where D = b^2 - 4*a*c - it is the discriminant.
Because
$$a = -2$$
$$b = -14$$
$$c = -20$$
, 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
$$x_{1} = -5$$
$$x_{2} = -2$$
Sum and product of roots
[src]
sum
-5 - 2
$$-5 - 2$$
=
-7
$$-7$$
product
-5*(-2)
$$- -10$$
=
10
$$10$$
10
The graph