\({4 \over 5 x} - {9 \over 5 x} = -{5 \over 5 x} = -{1 \over x}\)

\({9 \over a} + {6 \over 8 a} = {72 \over 8 a} + {6 \over 8 a} = {78 \over 8 a} = {39 \over 4 a}\)

\({3 \over 6 a} - {2 \over 7 b} = {21 b \over 42 a b} - {12 a \over 42 a b} = {21 b - 12 a \over 42 a b} = {7 b - 4 a \over 14 a b}\)

\(4 - {7 \over 6 x} = {4 \over 1} - {7 \over 6 x} = {24 x \over 6 x} - {7 \over 6 x} = {24 x - 7 \over 6 x}\)

\(2 p - {5 \over 9 p} = {2 p \over 1} ⋅ {9 p \over 9 p} - {5 \over 9 p} = {18 p^{2} \over 9 p} - {5 \over 9 p} = {18 p^{2} - 5 \over 9 p}\)

\({9 x \over y} - {7 \over 6 y} = {54 x \over 6 y} - {7 \over 6 y} = {54 x - 7 \over 6 y}\)

\({4 b \over 2 a} + {3 a \over 6 b} = {12 b^{2} \over 6 a b} + {3 a^{2} \over 6 a b} = {3 a^{2} + 12 b^{2} \over 6 a b} = {a^{2} + 4 b^{2} \over 2 a b}\)

\({2 p \over p} = {2 \over 1} = 2\)

\({x \over 6 x} = {1 \over 6}\)

\({-4 a \over -10 a} = \frac{2}{5}\)

\({-25 a \over 5 a} = -5\)

\({-9 a b \over 24 a c} = -{3 b \over 8 c}\)

\({30 q \over 35 p q} = {6 \over 7 p}\)

\({-30 x y z \over 5 y z} = -6 x\)

\({3 x y \over y} + {6 x z \over z} = 3 x + 6 x = 9 x\)

\({4 \over p} ⋅ {2 \over q} = {8 \over p q}\)

\({a \over 8} ⋅ -{4 \over b} = -{4 a \over 8 b} = -{a \over 2 b}\)

\({7 \over 5} ⋅ a = {7 a \over 5}\)

\({7 \over x} : {3 \over y} = {7 \over x} ⋅ {y \over 3} = {7 y \over 3 x}\)

\({7 \over 8} : x = {7 \over 8} : {x \over 1} = {7 \over 8} ⋅ {1 \over x} = {7 \over 8 x}\)

\({2 x \over 3} + {x - 6 \over 5} = {10 x \over 15} + {3 (x - 6) \over 15} = {10 x + 3 (x - 6) \over 15} = {13 x - 18 \over 15}\)

\(-{2 \over 9} : {x - y \over y} = -{2 \over 9} ⋅ {y \over x - y} = -{2 y \over 9 (x - y)} = -{2 y \over 9 x - 9 y}\)

\({4 a + 1 \over -3 a + 7} + 9 = {4 a + 1 \over -3 a + 7} - {-9 (-3 a + 7) \over -3 a + 7} = {4 a + 1 + 9 (-3 a + 7) \over -3 a + 7} = {4 a + 1 - 27 a + 63 \over -3 a + 7} = {-23 a + 64 \over -3 a + 7}\)