$1, \frac{-7}{12}+\frac{11}{8}-\frac{5}{9}$
$=\frac{-42}{72}+\frac{99}{72}-\frac{40}{72}$
$=\frac{-42+99-40}{72}$
$=\frac{17}{72}$
$2, \frac{1}{7}-\frac{8}{7}:8-3:\frac{3}{4}.2^{2}$
$=\frac{1}{7}-\frac{1}{7}-\frac{1}{4}.4$
$=-1$
$3, 1,4.\frac{15}{49}-(\frac{4}{5}+\frac{2}{3}):2\frac{1}{5}$
$=\frac{3}{7}-\frac{22}{15}:\frac{11}{5}$
$=\frac{3}{7}-\frac{2}{3}$
$=\frac{-5}{21}$