You need a solution of 5, so x must equal 5. I will put x as (5) for now. (5) = 5 You need multiplication, so multiply both sides by the same thing. 2(5) = 5*2 2(5) = 10
Now let's substitute 5 back in for x 2x = 10 Of course you can have a different equation by multiplying both sides by something different.