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受欢迎的代数 >

completesquare 4-x^2=5x

解答

4 - x^{2} = 5 x

解答

x = \frac{41 - 5}{2}, x = \frac{- 41 - 5}{2}

+1

十进制

x = 0.70156 \dots, x = - 5.70156 \dots

求解步骤

4 - x^{2} = 5 x

将

4

到右边

- x^{2} = 5 x - 4

将

5 x

para o lado esquerdo

- x^{2} - 5 x = - 4

两边除以

- 1

\frac{- x ^{2} - 5 x}{- 1} = \frac{- 4}{- 1}

x^{2} + 5 x = 4

改写为形式

(x + a)^{2} = b

(x + \frac{5}{2})^{2} = \frac{41}{4}

若

f^{2} (x) = a

，解为

f (x) = a, - a

解

x + \frac{5}{2} = \frac{41}{4} : x = \frac{41 - 5}{2}

解

x + \frac{5}{2} = - \frac{41}{4} : x = \frac{- 41 - 5}{2}

二次方程组的解是:

x = \frac{41 - 5}{2}, x = \frac{- 41 - 5}{2}

作图

流行的例子

solvefor x,2x^2y=7

so l v e f or x, 2 x^{2} y = 7

x^{(2)}-13x+42=0

x^{(2)} - 13 x + 42 = 0

(4-2sqrt(2))x^2-1=0

(4 - 22) x^{2} - 1 = 0

2 k^{2} - 3 k - 5 = 0

x^2+20^2=(36-10)^2

x^{2} + 2 0^{2} = (36 - 10)^{2}