Question

Please help me with the simplifying

Answer 1

The key here is to not worry too much and just follow PEMDAS.

Here we have the expression $(5\cdot 7)^2$.  Following PEMDAS, we complete the expression inside the parentheses first, or $5\cdot 7 = 35$. This gives us $(35)^2$ or just $35^2.$

Hope this helps.