1. P=(√x+1)(√2x−1)+(√2x+1)(√2x+√x)−(√2x+1)(√2x−1)(√2x+1)(√2x−1):(√2x+1)(√2x−1)+(√x+1)(√2x−1)−(√2x−√x)(√2x+1)(√2x+1)(√2x−1)
=√2x−√x+√2x−1+2x−√2x+√2x−√x−(2x−1)2x−1:2x−1+√2x−√x+√2x−1−(2x+√2x+√2x+√x)2x−1
=2√x(√2−1)2x−1:−2(√x+1)2x−1=2√x(√2−1)−2(√x+1)
2. Với x=3+2√22=(√2+1)22⇒√x=√2+1√2 thì:
P=2.√2+1√2.(√2−1)−2(√2+1√2+1)
=2.2−1√2−2.√2+1+√2√2=1−(2√2+1)