\({5 \over 7 x} - {8 \over 7 x} = -{3 \over 7 x}\)

\({9 \over a} - {8 \over 5 a} = {45 \over 5 a} - {8 \over 5 a} = {37 \over 5 a}\)

\({9 \over 6 a} - {2 \over 5 b} = {45 b \over 30 a b} - {12 a \over 30 a b} = {45 b - 12 a \over 30 a b} = {15 b - 4 a \over 10 a b}\)

\(9 - {2 \over 3 x} = {9 \over 1} - {2 \over 3 x} = {27 x \over 3 x} - {2 \over 3 x} = {27 x - 2 \over 3 x}\)

\({2 p \over q} + {4 \over 5 q} = {10 p \over 5 q} + {4 \over 5 q} = {10 p + 4 \over 5 q}\)

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

\({a \over 8 a} = {1 \over 8}\)

\({-16 x \over 20 x} = -\frac{4}{5}\)

\({-21 x \over 3 x} = -7\)

\({25 p q \over -40 p r} = -{5 q \over 8 r}\)

\({18 b \over -21 a b} = -{6 \over 7 a}\)

\({16 p q r \over -2 q r} = -8 p\)

\({3 x y \over y} - {5 x z \over z} = 3 x - 5 x = -2 x\)

\(9 a - {3 \over 2 a} = {9 a \over 1} ⋅ {2 a \over 2 a} - {3 \over 2 a} = {18 a^{2} \over 2 a} - {3 \over 2 a} = {18 a^{2} - 3 \over 2 a}\)

\({9 q \over 3 p} - {2 p \over 4 q} = {36 q^{2} \over 12 p q} - {6 p^{2} \over 12 p q} = {-6 p^{2} + 36 q^{2} \over 12 p q} = {-p^{2} + 6 q^{2} \over 2 p q}\)

\({4 \over a} ⋅ -{5 \over b} = -{20 \over a b}\)

\({x \over 6} ⋅ -{2 \over y} = -{2 x \over 6 y} = -{x \over 3 y}\)

\({8 \over 5} ⋅ x = {8 x \over 5}\)

\({4 b \over a} ⋅ {a + 7 \over 3} = {4 b (a + 7) \over 3 a} = {4 a b + 28 b \over 3 a}\)

\({3 \over a} : {7 \over b} = {3 \over a} ⋅ {b \over 7} = {3 b \over 7 a}\)

\(-{7 \over 4} : x = -{7 \over 4} : {x \over 1} = -{7 \over 4} ⋅ {1 \over x} = -{7 \over 4 x}\)

\({6 \over 5} : {x + 2 y \over y} = {6 \over 5} ⋅ {y \over x + 2 y} = {6 y \over 5 (x + 2 y)} = {6 y \over 5 x + 10 y}\)

\({p \over 8} + {p - 7 \over 5} = {5 p \over 40} + {8 (p - 7) \over 40} = {5 p + 8 (p - 7) \over 40} = {13 p - 56 \over 40}\)

\({-4 p - 3 \over -6 p + 5} + 8 = {-4 p - 3 \over -6 p + 5} - {-8 (-6 p + 5) \over -6 p + 5} = {-4 p - 3 + 8 (-6 p + 5) \over -6 p + 5} = {-4 p - 3 - 48 p + 40 \over -6 p + 5} = {-52 p + 37 \over -6 p + 5}\)

\({6 a^{2} - 3 a - 90 \over 3 a} = {6 a^{2} \over 3 a} - {3 a \over 3 a} - {90 \over 3 a} = 2 a - 1 - {30 \over a}\)

\({p^{2} + 8 p + 7 \over 2 p^{2}} = {p^{2} \over 2 p^{2}} + {8 p \over 2 p^{2}} + {7 \over 2 p^{2}} = \frac{1}{2} + {4 \over p} + {7 \over 2 p^{2}}\)