State, with the reason, which of the following are surds and which are not:
1) 180−−−√
2) 27−−√4
3) 128−−−√5
4) 64−−√3
5) 25−−√3⋅40−−√3
6) −125−−−−√3
7) π−−√
8) 3+2–√−−−−−−√
State, with the reason, which of the following are surds and which are not:
1) 180−−−√
2) 27−−√4
3) 128−−−√5
4) 64−−√3
5) 25−−√3⋅40−−√3
6) −125−−−−√3
7) π−−√
8) 3+2–√−−−−−−√