Multiply and combine like terms: (2x+1/6)^4
hint: (a+b)^4 = a^4 + 4*a^3*b + 6*a^2*b^2 + 4*a*b^3 + b^4. Can you take it from here?
Use binomial thoerem
4+1=5th row of pascal triangle
1,4,6,4,1
1 x^4
4x^3y
6x^2y^2
4xy^3
1 y^3
use this expansion of (x+y)^4