(2)原式=(2a-b-b)(2a-b+b) 12. 2²=(x+1/x)² 1.3(第一种)
= (2a-2b)(2a) 4=x²+2+1/x² 原式=(a+3-a+1)(a+3+a-1)
= 4a(a-b) x²+1/x²=2 =8(a+1)
代入值得=40 (第二种)
原式=a²+6a+9-a²+2a-1
=8a+8=8(a+1)
追问看不清楚,可以写在纸上照下来吗
追答很清楚啊,有不清楚的直接问吧
追问![](https://video.ask-data.xyz/img.php?b=https://iknow-pic.cdn.bcebos.com/b58f8c5494eef01f885ccf0be1fe9925bd317db0?x-bce-process=image%2Fresize%2Cm_lfit%2Cw_600%2Ch_800%2Climit_1%2Fquality%2Cq_85%2Fformat%2Cf_auto)
12题就没答案吗
追答12. 2²=(x+1/x)²
4=x²+2+1/x²
x²+1/x²=2
追问噢,已经解除来了