[tex]3a + 1 = -3.6(a - 1) \\\\3a + 1 = -3.6 a +3,6\ \ | \ add\ 3.6a\ to\ both\ sides \\ \\ 3a + 3.6a+1 = 3,6\ \ |\ subtract\ 1\ to\ both\ sides \\\\6.6a=3.6-1 \\\\ 6.6a=2.6 \ \ | \ multiply\ both\ sides\ by\ 10 \\\\66a=26 \ \ | \ divide \ both \ sides\ by\ 66\\\\a=\frac{26}{66}\\\\a=\frac{13}{33} [/tex]
