No, they are not equivalent. The first term, -4 1/2 equals 4 whole units and one half unit. All negative. So it’s like you have someone 4 and 1/2 dollars.
The second term, (-4)1/2 means multiplying -4 times 1/2. Doing the multiplication for this gives you -4/2. Solving the division here is -2. It’s taking away 1/2 dollar 4 times.
I hope this helped. Happy to answer any questions you have.