Solve for x: 1/5 (5x + 12) = 18

How would I go about solving this? ... I didn't understand the lesson too well and now I'm rather confused

Solution for 1/5 (5x+12) = 18 equation:

x in (-oo:+oo)

(1/5) * (5*x+12) = 18 / / - 18

(1/5) * (5*x+12) - 18 = 0

1/5 * (5*x+12) - 18 = 0

1/5 * (5*x+12) - 18 = 0

x-78/5 = 0

x-78/5 = 0

x-78/5 = 0 / / + 78/5

x = 78/5

x = 78/5

What happens is you take 1/5 and multiply it by 5x and 12. After that you get x + 2 2/5 = 18 Subtract 2 and 2/5 from birth sides of the equal sign and you get x=15 and 3/5