(n)=(n^2)/2-3 n/2

解答

(n) = \frac{n ^{2}}{2} - 3 \frac{n}{2}

n = 5, n = 0

求解步骤

(n) = \frac{n ^{2}}{2} - 3 \cdot \frac{n}{2}

在两边乘以

2

2 n = n^{2} - 3 n

交换两边

n^{2} - 3 n = 2 n

将

2 n

para o lado esquerdo

n^{2} - 5 n = 0

使用求根公式求解

n_{1, 2} = \frac{- ( - 5 ) \pm ( - 5 ) ^{2} - 4 \cdot 1 \cdot 0}{2 \cdot 1}

(- 5)^{2} - 4 \cdot 1 \cdot 0 = 5

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

将解分隔开

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

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

n = \frac{- ( - 5 ) - 5}{2 \cdot 1} : 0

二次方程组的解是:

n = 5, n = 0

x^{2} - x + 1 = 0, x = 1 x = - 1

so l v e f or x, 2 x \cdot (6 x - 2 y^{2}) + 3 y^{2} (x - 4) = 8

x^{2} + (m - 1) x + 2 m - 6 = 0

so l v e f or x, x^{2} + y^{3} + 2 x - 8 y - 113 = 130

\frac{( x ^{2} )}{9} - \frac{x}{2} = \frac{1}{3} + \frac{x}{9}