Question: simplify the expression y^4(y^2(y^5)^2)^3.
When you have a bracketed expression, start from the innermost bracket(s), and evaluate them first. Then work outwards.
The expression is: y^4(y^2(y^5)^2)^3
The innermost bracketed term is: (y^5)^2, and this evaluates to y^10.
The expression now is: y^4(y^2.y^10)^3
The innermost bracketed term is: (y^2.y^10), and this evaluates to y^12.
The expression now is: y^4(y^12)^3
The innermost bracketed term is: (y^12)^3, and this evaluates to y^36.
The expression now is: y^4.y^36, and this evaluates to : y^40.
Answer: y^40