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受欢迎的代数 >

solvefor x,x^2-xy=4

解答

求解

x, x^{2} - x y = 4

解答

x = \frac{y + y ^{2} + 16}{2}, x = \frac{y - y ^{2} + 16}{2}

求解步骤

x^{2} - x y = 4

将

4

para o lado esquerdo

x^{2} - x y - 4 = 0

改写成标准形式

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

x^{2} - y x - 4 = 0

使用求根公式求解

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

化简

(- y)^{2} - 4 \cdot 1 \cdot (- 4) : y^{2} + 16

x_{1, 2} = \frac{- ( - y ) \pm y ^{2} + 16}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- ( - y ) + y ^{2} + 16}{2 \cdot 1}, x_{2} = \frac{- ( - y ) - y ^{2} + 16}{2 \cdot 1}

x = \frac{- ( - y ) + y ^{2} + 16}{2 \cdot 1} : \frac{y + y ^{2} + 16}{2}

x = \frac{- ( - y ) - y ^{2} + 16}{2 \cdot 1} : \frac{y - y ^{2} + 16}{2}

二次方程组的解是:

x = \frac{y + y ^{2} + 16}{2}, x = \frac{y - y ^{2} + 16}{2}

作图

流行的例子

- 2 + 4 k^{2} = - 15

-(2x^2+7)=(2x+1)(x+3)

- (2 x^{2} + 7) = (2 x + 1) (x + 3)

0 = 4 x^{2} + 8 x + 4

x^{2} = 8 x - 19

x^{2} = 8 x - 23