题目内容

(1)计算:(3
2
-
12
)(
18
+2
3
)

(2)解方程:4(x-1)2-9(x-5)2=0.
(1)(3
2
-
12
)(
18
+2
3

=(3
2
-2
3
)(3
2
+2
3

=(3
2
2-(2
3
2
=18-12
=6;                                                
(2)4(x-1)2-9(x-5)2=0,
变形为:[2(x-1)]2-[3(x-5)]2=0,
因式分解得:[2(x-1)+3(x-5)][2(x-1)-3(x-5)]=0,
(2x-2+3x-15)(2x-2-3x+15)=0,即(5x-17)(-x+13)=0,
可化为5x-17=0或-x+13=0,
解得:x1=
17
5
,x2=13.
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