18) a+pa+ 6P-7 2 5 5 6 P

18) $$\frac{2}{7}$$a + $$\frac{1}{6}$$p - $$\frac{5}{7}$$a + $$\frac{5}{6}$$p = $$\frac{2}{7}$$a - $$\frac{5}{7}$$a + $$\frac{1}{6}$$p + $$\frac{5}{6}$$p = ($$\frac{2}{7}$$ - $$\frac{5}{7}$$)a + ($$\frac{1}{6}$$ + $$\frac{5}{6}$$)p = -$$\frac{3}{7}$$a + $$\frac{6}{6}$$p = -$$\frac{3}{7}$$a + p

Ответ: -$$\frac{3}{7}$$a+p