展开 (6sqrt(7)-5sqrt(5))(6sqrt(7+5\sqrt{5)})

解答

展开

(67 - 55) (6 7 + 55)

36 49 + 355 - 30 35 + 255

十进制

120.09111 \dots

求解步骤

(67 - 55) (6 7 + 55)

使用分配律:

a (b - c) = ab - a c

a = (6 7 + 55), b = 67, c = 55

= (6 7 + 55) \cdot 67 - (6 7 + 55) \cdot 55

= 67 (6 7 + 55) - 55 (6 7 + 55)

化简

67 (6 7 + 55) - 55 (6 7 + 55) : 36 49 + 355 - 30 35 + 255

= 36 49 + 355 - 30 35 + 255

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