\({4 \over 2 x} - {8 \over 2 x} = -{4 \over 2 x} = -{2 \over x}\)

\({4 \over x} - {9 \over 8 x} = {32 \over 8 x} - {9 \over 8 x} = {23 \over 8 x}\)

\({6 \over 9 a} - {7 \over 4 b} = {24 b \over 36 a b} - {63 a \over 36 a b} = {24 b - 63 a \over 36 a b} = {8 b - 21 a \over 12 a b}\)

\(4 - {6 \over 7 p} = {4 \over 1} - {6 \over 7 p} = {28 p \over 7 p} - {6 \over 7 p} = {28 p - 6 \over 7 p}\)

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

\({9 x \over y} - {4 \over 6 y} = {54 x \over 6 y} - {4 \over 6 y} = {54 x - 4 \over 6 y} = {27 x - 2 \over 3 y}\)

\({8 b \over 2 a} - {7 a \over 4 b} = {16 b^{2} \over 4 a b} - {7 a^{2} \over 4 a b} = {-7 a^{2} + 16 b^{2} \over 4 a b}\)

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

\({a \over 5 a} = {1 \over 5}\)

\({40 p \over -45 p} = -\frac{8}{9}\)

\({9 a \over -3 a} = -3\)

\({-9 x y \over -24 x z} = {3 y \over 8 z}\)

\({35 b \over -45 a b} = -{7 \over 9 a}\)

\({-24 p q r \over 3 q r} = -8 p\)

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

\({4 \over x} ⋅ {6 \over y} = {24 \over x y}\)

\({a \over 9} ⋅ {2 \over b} = {2 a \over 9 b}\)

\(-{1 \over 5} ⋅ a = -{a \over 5}\)

\({9 \over p} : {6 \over q} = {9 \over p} ⋅ {q \over 6} = {9 q \over 6 p} = {3 q \over 2 p}\)

\({5 \over 3} : x = {5 \over 3} : {x \over 1} = {5 \over 3} ⋅ {1 \over x} = {5 \over 3 x}\)

\({5 p \over 4} + {p - 7 \over 3} = {15 p \over 12} + {4 (p - 7) \over 12} = {15 p + 4 (p - 7) \over 12} = {19 p - 28 \over 12}\)