Since the angles are complementary, and that is a right angle, it is equal to 90°. So, we know that 4x+3x+6=90.
So, solve this for x. Combine like terms. The problem should now look like: 7x+6=90. Now, we need to isolate the x. Subtract 6 from 6, and subtract 6 from 90. This is because we must move the 6 to the other side of the problem to find x. Whatever we do on one side of the problem, we must do on the other. The problem should now look like 7x=84. Now, isolate the variable by dividing 7x by 7. Again, you must do the same thing to both sides of the problem. So, you must also divide 84 by 7.
