1) Subtract 15 from 28 =13 2) divide 13 by 5 =2.6 x=2.6

[latex]5x+15=28\ \ \ \ |subtract\ 15\ from\ both\ sides\\\\5x=13\ \ \ \ \ |divide\ both\ sides\ by\ 5\\\\x=\frac{13}{5}\\\\x=\frac{10+3}{5}\\\\x=\frac{10}{5}+\frac{3}{5}\\\\x=2+\frac{3}{5}\\\\\boxed{x=2\frac{3}{5}}[/latex]