展开 pir^2(r-7)

解答

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π r^{2} (r - 7)

π r^{3} - 7 π r^{2}

求解步骤

π r^{2} (r - 7)

使用分配律:

a (b - c) = ab - a c

a = π r^{2}, b = r, c = 7

= π r^{2} r - π r^{2} \cdot 7

= π r^{2} r - 7 π r^{2}

π r^{2} r = π r^{3}

= π r^{3} - 7 π r^{2}

e x p an d (2 x + 3 y = 7,) (6 x - y = 1)

e x p an d (1 + 5) e^{4}

e x p an d 4 (2 x + 3 y = 53)

e x p an d \frac{s}{( s ^{2} + 2 ) ^{2}}

e x p an d e^{7 x - 9} d (7 x - 9)