19x+12y=17
step 1: move the thing that you're looking for to the left side and all the rest to the right side:
(19x +12y)-19x = 17 -19x
12y = 17 -19x
step 2: to find y, you need to get rid of 12. to do so you need to devide everything by that number:
(12y)/12 = 17/12 -19/12 x
y= 17/12 -19/12 x
step 3: simplify of possible. ( in this exercise it isnt)
step 4: rearange the equation if necessary
y= 17/12 + -19/12x
y= -19/12x + 17/12
