Mister Exam
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How to use it?
- Equation:
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Equation cos(x)=√3/2
- Equation x^2-x-56=0
- Equation f*(x)=3
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Equation x^3=-8
- Express {x} in terms of y where:
- 3*x+10*y=-13
- 14*x+5*y=-18
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- 6*x-14*y=-9
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Identical expressions
- x^ two -x- fifty-six = zero
- x squared minus x minus 56 equally 0
- x to the power of two minus x minus fifty minus six equally zero
- x2-x-56=0
- x²-x-56=0
- x to the power of 2-x-56=0
- x^2-x-56=O
-
Similar expressions
- x^2+x-56=0
- x^2-x+56=0
x^2-x-56=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
$$a = 1$$
$$b = -1$$
$$c = -56$$
, then
Because D > 0, then the equation has two roots.
or
$$x_{1} = 8$$
$$x_{2} = -7$$
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
$$a = 1$$
$$b = -1$$
$$c = -56$$
, then
D = b^2 - 4 * a * c =
(-1)^2 - 4 * (1) * (-56) = 225
Because D > 0, then the equation has two roots.
x1 = (-b + sqrt(D)) / (2*a)
x2 = (-b - sqrt(D)) / (2*a)
or
$$x_{1} = 8$$
$$x_{2} = -7$$
Vieta's Theorem
it is reduced quadratic equation
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = -1$$
$$q = \frac{c}{a}$$
$$q = -56$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = 1$$
$$x_{1} x_{2} = -56$$
$$p x + q + x^{2} = 0$$
where
$$p = \frac{b}{a}$$
$$p = -1$$
$$q = \frac{c}{a}$$
$$q = -56$$
Vieta Formulas
$$x_{1} + x_{2} = - p$$
$$x_{1} x_{2} = q$$
$$x_{1} + x_{2} = 1$$
$$x_{1} x_{2} = -56$$
Sum and product of roots
[src]
sum
-7 + 8
$$-7 + 8$$
=
1
$$1$$
product
-7*8
$$- 56$$
=
-56
$$-56$$
-56