Z/3-3=z/4+7

Please help i don't understand this solving linear equations

the first step is usually to clear all the fractions by using the LCD. In this case 12. Do that and you have

z/3 - 3 = z/4 + 7
4z - 36 = 3z + 84
z = 120

Or, you can collect terms as usual, and then clear fractions

z/3 - 3 = z/4 + 7
z/3 - z/4 = 10
(1/3 - 1/4)z = 10
1/12 z = 10
z = 120