Hi, I've recently started doing proofs in math, and I've gotten through most of it, but I am still absolutely clueless when it comes to these questions; could someone please help and explain to me how this works??

Question 1: What is the reason for #4?

Given: 4x + 1 = 6x - 2, Prove: x = 3/2

(1) 4x + 1 = 6x - 2

(2) 4x + 3 = 6x

(3) 3 = 2x

(4) 3/2 = x ?

(5) x = 3/2

Question 2:

What is the reason for #3?

Given: 3x - 4 = 2(x + 8), Prove: x = 20

(1) 3x - 4 = 2(x + 8)

(2) 3x - 4 = 2x + 16

(3) 3x = 2x + 20 ?

(4) x = 20

PLEASE HELP I AM DESPERATE TO UNDERSTAND!!