Answer:
x = 28/(3y -15)
Explanation:
Put the x-terms on the same side of the equal sign and everything else on the other side. Divide by the coefficient of x.
3xy -28 = 15x . . . . . . given
-28 = 15x -3xy . . . . . subtract 3xy
-28 = x(15 -3y) . . . . . factor out x
-28/(15 -3y) = x . . . . . . divide by the coefficient of x
We prefer to have a positive sign where possible, so we can multiply this by -1/-1 to get ...
x = 28/(3y -15)