Answer with Step-by-step explanation:
The method uses the formula of the right angles triangle, more precisely the pythogorean formula,
In step 2, it is the power law of indices,
Other than this, other tricks used here is the using of square root on step no 6.
You can take the square root ,cube root, square, etc in equations but you have to do it on both sides, you can even add r subtract numbers and do all sorts of things.
it is the process of solving equations by equality.
Eg:
x=5
x^2=5^2
√x=√x
x-7=5-7
8/2x=8/2*5, etc