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受欢迎的代数 >

(n)=n^2-4n+20

解答

(n) = n^{2} - 4 n + 20

解答

n = \frac{5}{2} + i \frac{55}{2}, n = \frac{5}{2} - i \frac{55}{2}

求解步骤

(n) = n^{2} - 4 n + 20

整理后得

n = n^{2} - 4 n + 20

交换两边

n^{2} - 4 n + 20 = n

将

n

para o lado esquerdo

n^{2} - 5 n + 20 = 0

使用求根公式求解

n_{1, 2} = \frac{- ( - 5 ) \pm ( - 5 ) ^{2} - 4 \cdot 1 \cdot 20}{2 \cdot 1}

化简

(- 5)^{2} - 4 \cdot 1 \cdot 20 : 55 i

n_{1, 2} = \frac{- ( - 5 ) \pm 55 i}{2 \cdot 1}

将解分隔开

n_{1} = \frac{- ( - 5 ) + 55 i}{2 \cdot 1}, n_{2} = \frac{- ( - 5 ) - 55 i}{2 \cdot 1}

n = \frac{- ( - 5 ) + 55 i}{2 \cdot 1} : \frac{5}{2} + i \frac{55}{2}

n = \frac{- ( - 5 ) - 55 i}{2 \cdot 1} : \frac{5}{2} - i \frac{55}{2}

二次方程组的解是:

n = \frac{5}{2} + i \frac{55}{2}, n = \frac{5}{2} - i \frac{55}{2}

作图

流行的例子

- x^{2} + 7 x = 11.25

completesquare w^2-10w

co m pl e t es q u a re w^{2} - 10 w

r^{2} + r - 4 = 0

(h + 1)^{2} = 16

x^{2} + 11 x = 180