问题
解答题
(1)计算:9
(2)解方程:2(x+2)2=x2-4. |
答案
(1)9
÷345
-1 10
×3 2 6 2 2 3
=9
×45
-10 3
×3 2 6 8 3
=3
-450 8
=45
-22 2
=43
;2
(2)2(x+2)2=x2-4,
2(x+2)2=(x+2)(x-2),
2(x+2)2-(x+2)(x-2)=0,
(x+2)[2(x+2)-(x-2)]=0,
即(x+2)(x+6)=0,
可化为:x+2=0或x+6=0,
解得:x1=-2,x2=-6.