4n^2-8n+90=9

解答

4 n^{2} - 8 n + 90 = 9

n = 1 + i \frac{77}{2}, n = 1 - i \frac{77}{2}

求解步骤

4 n^{2} - 8 n + 90 = 9

将

9

para o lado esquerdo

4 n^{2} - 8 n + 81 = 0

使用求根公式求解

n_{1, 2} = \frac{- ( - 8 ) \pm ( - 8 ) ^{2} - 4 \cdot 4 \cdot 81}{2 \cdot 4}

化简

(- 8)^{2} - 4 \cdot 4 \cdot 81 : 477 i

n_{1, 2} = \frac{- ( - 8 ) \pm 4 77 i}{2 \cdot 4}

将解分隔开

n_{1} = \frac{- ( - 8 ) + 4 77 i}{2 \cdot 4}, n_{2} = \frac{- ( - 8 ) - 4 77 i}{2 \cdot 4}

n = \frac{- ( - 8 ) + 4 77 i}{2 \cdot 4} : 1 + i \frac{77}{2}

n = \frac{- ( - 8 ) - 4 77 i}{2 \cdot 4} : 1 - i \frac{77}{2}

二次方程组的解是:

n = 1 + i \frac{77}{2}, n = 1 - i \frac{77}{2}

so l v e f or x, h + g = x^{2}

so l v e f or f, ff = \frac{- 2 x}{3 x - 4}

so l v e f or y, y^{2} - 4 y + C = x^{3} + 2 x^{2} - 4 x + C

- 6 x (x - 7) = 4 (x + 7) + 4 x

0.44 x^{2} - 1.06 x + 0.786 = 0