4x+5=6x-13. Take 4x from both sides 5= 6x-4x-13 5=2x-13. On the right hand side, you have -13 value. Add 13, to make 0. Adding thirteen on right also adds thirteen on left. 5 + 13 = 2x - 13 + 13 18=2x. 2 times 'x' is 18. You might automatically know that 2 times 9 is 18, but it is good practice to use algebra here, as you will not always get a full number and may end up with fractions. If you divide by 2 on both sides, you get 2x/2 = 18/2 x=9. Always show your working, so the examiner knows what you are trying to do and can give you marks for at least showing your algebra skills.