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受欢迎的代数 >

(2x-3/4)(x-1/2)=31

解答

(2 x - \frac{3}{4}) (x - \frac{1}{2}) = 31

解答

x = \frac{35}{8}, x = - \frac{7}{2}

+1

十进制

x = 4.375, x = - 3.5

求解步骤

(2 x - \frac{3}{4}) (x - \frac{1}{2}) = 31

展开

(2 x - \frac{3}{4}) (x - \frac{1}{2}) : 2 x^{2} - \frac{7}{4} x + \frac{3}{8}

2 x^{2} - \frac{7}{4} x + \frac{3}{8} = 31

将

31

para o lado esquerdo

- \frac{245}{8} - \frac{7}{4} x + 2 x^{2} = 0

改写成标准形式

a x^{2} + b x + c = 0

2 x^{2} - \frac{7 x}{4} - \frac{245}{8} = 0

使用求根公式求解

x_{1, 2} = \frac{- ( - \frac{7}{4} ) \pm ( - \frac{7}{4} ) ^{2} - 4 \cdot 2 ( - \frac{245}{8} )}{2 \cdot 2}

(- \frac{7}{4})^{2} - 4 \cdot 2 (- \frac{245}{8}) = \frac{63}{4}

x_{1, 2} = \frac{- ( - \frac{7}{4} ) \pm \frac{63}{4}}{2 \cdot 2}

将解分隔开

x_{1} = \frac{- ( - \frac{7}{4} ) + \frac{63}{4}}{2 \cdot 2}, x_{2} = \frac{- ( - \frac{7}{4} ) - \frac{63}{4}}{2 \cdot 2}

x = \frac{- ( - \frac{7}{4} ) + \frac{63}{4}}{2 \cdot 2} : \frac{35}{8}

x = \frac{- ( - \frac{7}{4} ) - \frac{63}{4}}{2 \cdot 2} : - \frac{7}{2}

二次方程组的解是:

x = \frac{35}{8}, x = - \frac{7}{2}

作图

流行的例子

化简 (142.17(1.2))/((32.11)(79.1))

s im pl i f y \frac{142.17 ( 1.2 )}{( 32.11 ) ( 79.1 )}

9 \leq 2 m + 2 - 3

a^{2} + 6 a + 9 = 0

s im pl i f y 15 \cdot \frac{1}{2}

log_{25}(1/5)=x

lo g_{25} (\frac{1}{5}) = x