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受欢迎的代数 >

9r(r-2)=r^2+5

解答

9 r (r - 2) = r^{2} + 5

解答

r = \frac{5}{2}, r = - \frac{1}{4}

+1

十进制

r = 2.5, r = - 0.25

求解步骤

9 r (r - 2) = r^{2} + 5

展开

9 r (r - 2) : 9 r^{2} - 18 r

9 r^{2} - 18 r = r^{2} + 5

将

5

para o lado esquerdo

9 r^{2} - 18 r - 5 = r^{2}

将

r^{2}

para o lado esquerdo

8 r^{2} - 18 r - 5 = 0

使用求根公式求解

r_{1, 2} = \frac{- ( - 18 ) \pm ( - 18 ) ^{2} - 4 \cdot 8 ( - 5 )}{2 \cdot 8}

(- 18)^{2} - 4 \cdot 8 (- 5) = 22

r_{1, 2} = \frac{- ( - 18 ) \pm 22}{2 \cdot 8}

将解分隔开

r_{1} = \frac{- ( - 18 ) + 22}{2 \cdot 8}, r_{2} = \frac{- ( - 18 ) - 22}{2 \cdot 8}

r = \frac{- ( - 18 ) + 22}{2 \cdot 8} : \frac{5}{2}

r = \frac{- ( - 18 ) - 22}{2 \cdot 8} : - \frac{1}{4}

二次方程组的解是:

r = \frac{5}{2}, r = - \frac{1}{4}

作图

流行的例子

16 x^{2} + 24 x + 5 = 0

solvefor y,-3y^2z-3yz^2=21

so l v e f or y, - 3 y^{2} z - 3 y z^{2} = 21

p^{2} + 14 p + 49 = 2

w^{2} + 16 w + 64 = 0

5 = x^{2} + 4 x