(There are many different answers you could give, here are 2 examples)
5x + 2 = 3x + 4
6x + 4 = 7x + 3
To do this, just remember that if x = 1, then it doesn’t really change anything (since any number times 1, is just the original number (ex. 3 times 1 is 3)).
So, you can pick a random number you want both equations to be equal to, then pick different numbers that add to the random number.
Example: for my first equation, I wanted both sides to be equal to 7. So I though, “what numbers add together to give you 7?”. ( 5 + 2 = 7, and 3 + 4 = 7)
In terms of what you notice about the equation, there are different things you could say, but an example could be “both sides of the equations when added together equal the same number”