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受欢迎的代数 >

solvefor x,x^2+xy+2y^2=18

解答

求解

x, x^{2} + x y + 2 y^{2} = 18

解答

x = \frac{- y + - 7 y ^{2} + 72}{2}, x = \frac{- y - - 7 y ^{2} + 72}{2}

求解步骤

x^{2} + x y + 2 y^{2} = 18

将

18

para o lado esquerdo

x^{2} + x y + 2 y^{2} - 18 = 0

改写成标准形式

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

x^{2} + y x + 2 y^{2} - 18 = 0

使用求根公式求解

x_{1, 2} = \frac{- y \pm y ^{2} - 4 \cdot 1 \cdot ( 2 y ^{2} - 18 )}{2 \cdot 1}

化简

y^{2} - 4 \cdot 1 \cdot (2 y^{2} - 18) : - 7 y^{2} + 72

x_{1, 2} = \frac{- y \pm - 7 y ^{2} + 72}{2 \cdot 1}

将解分隔开

x_{1} = \frac{- y + - 7 y ^{2} + 72}{2 \cdot 1}, x_{2} = \frac{- y - - 7 y ^{2} + 72}{2 \cdot 1}

x = \frac{- y + - 7 y ^{2} + 72}{2 \cdot 1} : \frac{- y + - 7 y ^{2} + 72}{2}

x = \frac{- y - - 7 y ^{2} + 72}{2 \cdot 1} : \frac{- y - - 7 y ^{2} + 72}{2}

二次方程组的解是:

x = \frac{- y + - 7 y ^{2} + 72}{2}, x = \frac{- y - - 7 y ^{2} + 72}{2}

作图

流行的例子

x^{2} + 8 = 20

(1 + y)^{2} + y^{2} = 25

x^{2} - 50 x + 225 = 0

(2x+3)^2-14x-21=-6

(2 x + 3)^{2} - 14 x - 21 = - 6

solvefor x,y^4=4x^2+6xy

so l v e f or x, y^{4} = 4 x^{2} + 6 x y