1.-[a+b]^5*[a+b]^2
=-(a+b)^(2+5)
=-(a+b)^7
2.a^2n+1*a^2n-1
=a^(2n+1+2n-1)
=a^4n
3.10^4*10^÷10^-2
=10^(4+2-(-2))
=10^8
4.[1/7]^0÷[-1/7]^-1
=1÷(-7)
=-1/7
5.[x+2y+3z][x+2y-3z]
=(x+2y)²-(3z)²
=x²+4xy+4y²-9z²