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Popular >

x^2-20x-21=0

Solution

x^{2} - 20 x - 21 = 0

Solution

x = 21, x = - 1

Solution steps

x^{2} - 20 x - 21 = 0

Solve with the quadratic formula

x_{1, 2} = \frac{- ( - 20 ) \pm ( - 20 ) ^{2} - 4 \cdot 1 \cdot ( - 21 )}{2 \cdot 1}

(- 20)^{2} - 4 \cdot 1 \cdot (- 21) = 22

x_{1, 2} = \frac{- ( - 20 ) \pm 22}{2 \cdot 1}

Separate the solutions

x_{1} = \frac{- ( - 20 ) + 22}{2 \cdot 1}, x_{2} = \frac{- ( - 20 ) - 22}{2 \cdot 1}

x = \frac{- ( - 20 ) + 22}{2 \cdot 1} : 21

x = \frac{- ( - 20 ) - 22}{2 \cdot 1} : - 1

The solutions to the quadratic equation are:

x = 21, x = - 1

Popular Examples

-3x^2+35x-22-(-4x^2+3x-71)=0

- 3 x^{2} + 35 x - 22 - (- 4 x^{2} + 3 x - 71) = 0

33^2=30.6^2+v^2

3 3^{2} = 30. 6^{2} + v^{2}

solvefor t,0-75=15.5*t+1/2*(-9.8)*t^2 solve for

t, 0 - 75 = 15.5 \cdot t + \frac{1}{2} \cdot (- 9.8) \cdot t^{2}

x^2-2x+2=0,x^2-2x+4=0

x^{2} - 2 x + 2 = 0, x^{2} - 2 x + 4 = 0

completesquare 2.1x^2-6.1x+3900=4000000 complete the square

2.1 x^{2} - 6.1 x + 3900 = 4000000

Frequently Asked Questions (FAQ)

What are the solutions to the equation x^2-20x-21=0 ?
The solutions to the equation x^2-20x-21=0 are x=21,x=-1
Find the zeros of x^2-20x-21=0
The zeros of x^2-20x-21=0 are x=21,x=-1