\(\left(\dfrac{1}{2}\right)^{15}.\left(\dfrac{1}{4}\right)^{20}=\left(\dfrac{1}{2}\right)^{15}.\left(\dfrac{1}{2}\right)^{40}=\left(\dfrac{1}{2}\right)^{55}\)
Mình không chắc là đúng đâu 
\(\left(\dfrac{1}{2}\right)^{15}.\left(\dfrac{1}{4}\right)^{20}=\left(\dfrac{1}{2}\right)^{15}.\left[\left(\dfrac{1}{2}\right)^2\right]^{20}=\left(\dfrac{1}{2}\right)^{15}.\left(\dfrac{1}{2}\right)^{40}=\left(\dfrac{1}{2}\right)^{55}\)
(1/2)^15. (1/4)^20
= (1/2)^15. (1/2)^2. 20
= (1/2)^15. (1/2)^40
= (1/2)^15.40
= (1/2)^600
