(-2x^4)^2

y

Again I will assume you mean:

(-2x^4)^2 / y

-2 *-2 = + 4
x^4 * x^4 = x^8
so
4 x^8 / y
which is the same as
4 x^8 y^-1

Here is a link to instructions:

http://www.mathsisfun.com/algebra/variables-exponents-multiply.html

Then to raise one power to another see:

http://mathsfirst.massey.ac.nz/Algebra/Exponents/IntegerExp/RaisePower.htm

I am doing polynomials, is that the same

yes :)

although a polynomial normally has more than one term

for example
x^2 + 2 x + y + y^3 .........

Thank you :)

You are welcome

poly means more than one or many in general

To simplify the expression (-2x^4)^2, we first need to apply the exponent to both the base (-2x^4) and the exponent 2.

Applying the exponent 2 to the base (-2x^4), we multiply the exponent of each factor within the base by 2:

(-2x^4)^2 = (-2)^2 * (x^4)^2

Now we simplify each part separately.

(-2)^2 = 4 (square of -2)

(x^4)^2 = x^(4*2) = x^8 (when we have an exponent raised to another exponent, we multiply the exponents)

Putting it all together, we have:

(-2x^4)^2 = (-2)^2 * (x^4)^2 = 4 * x^8

So the simplified expression is 4x^8.

Regarding the "y" part of your question, I'm not sure what you're asking. Could you please provide more context or clarify your question?