Answer: 20
Step-by-step explanation:
Everything within the parenthesis gets an exponent of two, so you should have (x^2+y^2).
After this, you plug in the 'x' and 'y' given, so the next part should look like (2^2+(-4)^2)
After step 2, do 2*2 and -4*-4 (exponents ask you to multiply numbers by a specific amount. In this case, both numbers are multiplied by themselves 2 times).
A negative times a negative is a positive, so -4^2 or -4*-4 is 16. 2^2 or 2*2 is simply 4.
Add 4 and 16 together to get your final answer of 20.
Hope this helps!