Simplify 5(1+3)^2. best answer appreciated.

80 or 5(4)^2 
you first do parenthesis and then the square root 
so you would have 5(4)^2
Then, you would do the square root and it would come out to
5(16)
You can simply multiply from there, 80.

The answer you are looking for is 80.

This can be found by using PEMDAS. First you'd solve the parenthesis. 1 + 3 = 4.
Next you'd solve the exponents. 4 ^ 2 (4 * 4) = 16.
Finally you'd multiply 16 by 5 to get an answer of 80.

I hope this helps!

1603 is the correct one.