(2x-3)(2x+3)-135=0

解答

(2 x - 3) (2 x + 3) - 135 = 0

x = 6, x = - 6

求解步骤

(2 x - 3) (2 x + 3) - 135 = 0

展开

(2 x - 3) (2 x + 3) - 135 : 4 x^{2} - 144

4 x^{2} - 144 = 0

使用求根公式求解

x_{1, 2} = \frac{- 0 \pm 0 ^{2} - 4 \cdot 4 ( - 144 )}{2 \cdot 4}

0^{2} - 4 \cdot 4 (- 144) = 48

x_{1, 2} = \frac{- 0 \pm 48}{2 \cdot 4}

将解分隔开

x_{1} = \frac{- 0 + 48}{2 \cdot 4}, x_{2} = \frac{- 0 - 48}{2 \cdot 4}

x = \frac{- 0 + 48}{2 \cdot 4} : 6

x = \frac{- 0 - 48}{2 \cdot 4} : - 6

二次方程组的解是:

x = 6, x = - 6

2 x^{2} + 3 x - 5 = (x + 1)^{2}

(x - 1)^{2} > 0

- 1 j + 1 > 10

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

50 \leq 0.004 x^{2} - x + 80