If you could explain how to solve this, that'd be great!

Here, Expression: y⁴ / y

Now, subtract the exponential of numerator from denominator's

So, = y⁴⁻¹ = y³

In short, Your Answer would be: y³

Hope this helps!

One must look know their exponent rules... one rule states that when dividing two exponents, you subtract the divisor from the dividend.

Therefore...

y⁴/y¹ = y^(4-1) = y³