3x-4<2x+6 is an inequality, not an equation. There is no unique answer as there usually would be with an equation, where one side of the equation must balance the other side. However, we solve inequalities using similar techniques to those used in solving an equation.
So let's add 4 to each side of the inequality: 3x<2x+10; now subtract 2x from each side: x<10, which is the solution: any number less than 10 satisfies the inequality. 10 or any number bigger than 10 does not satisfy the inequality.