The first one is a big-theta of 2^n, and then also the other is a big-theta of 2^n because there is a constant that divide n.
Is that correct?
No, they are not equal asymptotically.
You should be able to find constants k1 and k2 for functions k1*2n and k2*2n that will bound 2n/10. We know that 2n/10 = (2n)(1/10) which cannot be expressed as c*2n.
2^(n/10)=(2^(1/10))^n not same as 2^n
See this Are 2^n and 4^n in the same Big-Θ complexity class?
the link explain 2^n and 4^n