a: \(2022^{x-2021}+3=\left(7-5\right)^2\)
=>\(2022^{x-2021}+3=4\)
=>\(2022^{x-2021}=1\)
=>x-2021=0
=>x=2021
b: \(\left(x+1\right)+\left(x+2\right)+...+\left(x+30\right)=795\)
=>\(30x+\left(1+2+3+...+30\right)=795\)
=>\(30x+\dfrac{30\cdot31}{2}=795\)
=>\(30x=795-31\cdot15=330\)
=>x=11