问题
解答题
计算或求 (1)5x2-
(2)64(x-1)3+125=0 (3)
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答案
(1)5x2-
=01 5
5x2=1 5
x2=1 25
x=±
;1 5
(2)64 (x-1)3+125=0
64 (x-1)3=-125
(x-1)3=-125 64
x-1=-3 125 64
x-1=-5 4
x=1-5 4
x=-
;1 4
(3)原式=
-2-1 5
-25 25 16 25
=
-2-1 5 9 25
=
-2-1 5 3 5
=-2
.2 5