Mister Exam
Other calculators
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How to use it?
- Equation:
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Equation x^2+4*x+4=0
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Equation 90+x-4*10=60
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Equation 6*3+x=72
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Equation x^3+x^2=0
- Express {x} in terms of y where:
- -4*x+19*y=-13
- -5*x-6*y=-1
- -16*x-2*y=4
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- Factor squared:
- x^2-7*x+4
-
Identical expressions
- x^ two - seven *x+ four = zero
- x squared minus 7 multiply by x plus 4 equally 0
- x to the power of two minus seven multiply by x plus four equally zero
- x2-7*x+4=0
- x²-7*x+4=0
- x to the power of 2-7*x+4=0
- x^2-7x+4=0
- x2-7x+4=0
- x^2-7*x+4=O
-
Similar expressions
- x^2-7*x-4=0
- x^2+7*x+4=0
x^2-7*x+4=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
$$a = 1$$
$$b = -7$$
$$c = 4$$
, then
Because D > 0, then the equation has two roots.
or
$$x_{1} = \frac{\sqrt{33}}{2} + \frac{7}{2}$$
$$x_{2} = \frac{7}{2} - \frac{\sqrt{33}}{2}$$
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
$$a = 1$$
$$b = -7$$
$$c = 4$$
, then
D = b^2 - 4 * a * c =
(-7)^2 - 4 * (1) * (4) = 33
Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
or
$$x_{1} = \frac{\sqrt{33}}{2} + \frac{7}{2}$$
$$x_{2} = \frac{7}{2} - \frac{\sqrt{33}}{2}$$
Vieta's Theorem
it is reduced quadratic equation
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = -7$$
$$q = \frac{c}{a}$$
$$q = 4$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = 7$$
$$x_{1} x_{2} = 4$$
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = -7$$
$$q = \frac{c}{a}$$
$$q = 4$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = 7$$
$$x_{1} x_{2} = 4$$
Rapid solution
[src]
____
7 \/ 33
x1 = - - ------
2 2
$$x_{1} = \frac{7}{2} - \frac{\sqrt{33}}{2}$$
____
7 \/ 33
x2 = - + ------
2 2
$$x_{2} = \frac{\sqrt{33}}{2} + \frac{7}{2}$$
x2 = sqrt(33)/2 + 7/2
Sum and product of roots
[src]
sum
____ ____ 7 \/ 33 7 \/ 33 - - ------ + - + ------ 2 2 2 2
$$\left(\frac{7}{2} - \frac{\sqrt{33}}{2}\right) + \left(\frac{\sqrt{33}}{2} + \frac{7}{2}\right)$$
=
7
$$7$$
product
/ ____\ / ____\ |7 \/ 33 | |7 \/ 33 | |- - ------|*|- + ------| \2 2 / \2 2 /
$$\left(\frac{7}{2} - \frac{\sqrt{33}}{2}\right) \left(\frac{\sqrt{33}}{2} + \frac{7}{2}\right)$$
=
4
$$4$$
4
The graph