展开 (k(3k-1))/2+(3k-1)

解答

展开

\frac{k ( 3 k - 1 )}{2} + (3 k - 1)

\frac{3 k ^{2}}{2} - \frac{k}{2} + 3 k - 1

求解步骤

\frac{k ( 3 k - 1 )}{2} + (3 k - 1)

去除括号:

(a) = a

= \frac{k ( 3 k - 1 )}{2} + 3 k - 1

乘开

k (3 k - 1) : 3 k^{2} - k

= \frac{3 k ^{2} - k}{2} + 3 k - 1

使用分式法则:

\frac{a \pm b}{c} = \frac{a}{c} \pm \frac{b}{c}

\frac{3 k ^{2} - k}{2} = \frac{3 k ^{2}}{2} - \frac{k}{2}

= \frac{3 k ^{2}}{2} - \frac{k}{2} + 3 k - 1

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