you multiply 2 and 3n which gives you 6n
then 2 x4 is 8
you get 6n+8 for the first equation
you multiply -2 and 2n is -4
multiply -2 and 5 is -10
you then have 6n+8-4n-10
combine like terms (6n and -4n)which is 2n
you end up with 2n+8-10
you subtract 8 on both sides of equation and get 2n-18
you divide 2 on both sides to end up with n-9 ←←←