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受欢迎的代数 >

solvefor y,s(y)=5yy+7

解答

求解

y, s (y) = 5 yy + 7

解答

y = \frac{s + s ^{2} - 140}{10}, y = \frac{s - s ^{2} - 140}{10}

求解步骤

s (y) = 5 yy + 7

展开

5 yy + 7 : 5 y^{2} + 7

ys = 5 y^{2} + 7

交换两边

5 y^{2} + 7 = ys

将

ys

para o lado esquerdo

5 y^{2} + 7 - ys = 0

改写成标准形式

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

5 y^{2} - sy + 7 = 0

使用求根公式求解

y_{1, 2} = \frac{- ( - s ) \pm ( - s ) ^{2} - 4 \cdot 5 \cdot 7}{2 \cdot 5}

化简

(- s)^{2} - 4 \cdot 5 \cdot 7 : s^{2} - 140

y_{1, 2} = \frac{- ( - s ) \pm s ^{2} - 140}{2 \cdot 5}

将解分隔开

y_{1} = \frac{- ( - s ) + s ^{2} - 140}{2 \cdot 5}, y_{2} = \frac{- ( - s ) - s ^{2} - 140}{2 \cdot 5}

y = \frac{- ( - s ) + s ^{2} - 140}{2 \cdot 5} : \frac{s + s ^{2} - 140}{10}

y = \frac{- ( - s ) - s ^{2} - 140}{2 \cdot 5} : \frac{s - s ^{2} - 140}{10}

二次方程组的解是:

y = \frac{s + s ^{2} - 140}{10}, y = \frac{s - s ^{2} - 140}{10}

作图

流行的例子

completesquare 1-4x-2x^2

co m pl e t es q u a re 1 - 4 x - 2 x^{2}

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

t^{2} = - 3 t - 4

8 y^{2} - y + 2 = 0

u^{2} - 4 u = 0