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人気のある代数 >

x^2-21x-5=0

解

x^{2} - 21 x - 5 = 0

解

x = \frac{21 + 461}{2}, x = \frac{21 - 461}{2}

+1

十進法表記

x = 21.23545 \dots, x = - 0.23545 \dots

解答ステップ

x^{2} - 21 x - 5 = 0

解くとthe二次式

x_{1, 2} = \frac{- ( - 21 ) \pm ( - 21 ) ^{2} - 4 \cdot 1 \cdot ( - 5 )}{2 \cdot 1}

(- 21)^{2} - 4 \cdot 1 \cdot (- 5) = 461

x_{1, 2} = \frac{- ( - 21 ) \pm 461}{2 \cdot 1}

解を分離する

x_{1} = \frac{- ( - 21 ) + 461}{2 \cdot 1}, x_{2} = \frac{- ( - 21 ) - 461}{2 \cdot 1}

x = \frac{- ( - 21 ) + 461}{2 \cdot 1} : \frac{21 + 461}{2}

x = \frac{- ( - 21 ) - 461}{2 \cdot 1} : \frac{21 - 461}{2}

二次equationの解:

x = \frac{21 + 461}{2}, x = \frac{21 - 461}{2}

グラフ

人気の例

quadraticformula 3x+18=x^2

q u a d r a t i c f or m u l a 3 x + 18 = x^{2}

(6 - x)^{2} = 64

solvefor x,f(x+3)=3x^2+3x-3

so l v e f or x, f (x + 3) = 3 x^{2} + 3 x - 3

(2-x)(x+1)-x(x-1)=2

(2 - x) (x + 1) - x (x - 1) = 2

18=(-6+3)^2+(2-y)^2

18 = (- 6 + 3)^{2} + (2 - y)^{2}