展开 (sqrt(5)+3)sqrt(8-2\sqrt{5)}

解答

展开

(5 + 3) 8 - 25

40 - 105 + 3 8 - 25

十进制

9.83470 \dots

求解步骤

(5 + 3) 8 - 25

使用分配律:

a (b + c) = ab + a c

a = 8 - 25, b = 5, c = 3

= 8 - 25 5 + 8 - 25 \cdot 3

= 5 8 - 25 + 3 8 - 25

5 8 - 25 = 40 - 105

= 40 - 105 + 3 8 - 25

e x p an d \frac{x ( x + 8 )}{2}

so l v e f or y, 3 y + 5 x = 6

e x p an d (x - u) d x - (x + 3 u) (u d x + x d u)

e x p an d c u r l (4 y x^{2}, x + 3 x y^{2})

e x p an d 2 0^{2}