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受欢迎的代数 >

4a^2+20a=-9

解答

4 a^{2} + 20 a = - 9

解答

a = - \frac{1}{2}, a = - \frac{9}{2}

+1

十进制

a = - 0.5, a = - 4.5

求解步骤

4 a^{2} + 20 a = - 9

将

9

para o lado esquerdo

4 a^{2} + 20 a + 9 = 0

使用求根公式求解

a_{1, 2} = \frac{- 20 \pm 2 0 ^{2} - 4 \cdot 4 \cdot 9}{2 \cdot 4}

2 0^{2} - 4 \cdot 4 \cdot 9 = 16

a_{1, 2} = \frac{- 20 \pm 16}{2 \cdot 4}

将解分隔开

a_{1} = \frac{- 20 + 16}{2 \cdot 4}, a_{2} = \frac{- 20 - 16}{2 \cdot 4}

a = \frac{- 20 + 16}{2 \cdot 4} : - \frac{1}{2}

a = \frac{- 20 - 16}{2 \cdot 4} : - \frac{9}{2}

二次方程组的解是:

a = - \frac{1}{2}, a = - \frac{9}{2}

作图

流行的例子

75+2.5x<= 195.5

75 + 2.5 x \leq 195.5

(2 x - 5) (x + 3) = 0

|(2x-1)/9 |<= 5/9

\frac{2 x - 1}{9} \leq \frac{5}{9}

因式分解 3r^2-10r+8

f a c t or 3 r^{2} - 10 r + 8

1/6 <= (2x-13)/(12)<= 2/3

\frac{1}{6} \leq \frac{2 x - 13}{12} \leq \frac{2}{3}