求下列各式中x的值:81(x-1)的平方-25=0
问题描述:
求下列各式中x的值:81(x-1)的平方-25=0
答
(x-1)的平方=25/81,x-1=正负5/9.x1=5/9 1,x2=5/9-1.
答
81(x-1)² - 25 = 0
81(x-1)² = 25
(x-1)² = 25/81
x - 1 = ± 5/9
x = 1 ± 5/9
x1 = 14/9
x2 = 4/9
答
81(x-1)的平方-25=0
(x-1)的平方=25/81
x-1=5/9
x=14/9
*写成带分数是1又9分子5
答
81(x-1)的平方-25=0
[9(x-1)+5][9(x-1)-5]=0
(9x-4)(9x-14)=0
x=4/9
x=14/9
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