9th grade algebra simple radical equation problem

Can someone explain to me how to do this problem I missed class the answer should be 25

√4x=10

The square root of 4x is equal to 10.
If you square the square root of 4x you will get that 4x = 100.
Now you simply divide by 4 to isolate "x" and the answer should be x = 25. :)

sqrt(4x)=10

square both sides

4x=100

divide by 4

x=25