\({3 \over 5 a} + {9 \over 5 a} = {12 \over 5 a}\)

\({8 \over p} + {5 \over 7 p} = {56 \over 7 p} + {5 \over 7 p} = {61 \over 7 p}\)

\({7 \over 8 x} - {6 \over 4 y} = {7 y \over 8 x y} - {12 x \over 8 x y} = {7 y - 12 x \over 8 x y}\)

\(6 + {7 \over 5 a} = {6 \over 1} + {7 \over 5 a} = {30 a \over 5 a} + {7 \over 5 a} = {30 a + 7 \over 5 a}\)

\({3 x \over y} + {8 \over 5 y} = {15 x \over 5 y} + {8 \over 5 y} = {15 x + 8 \over 5 y}\)

\({9 x \over x} = {9 \over 1} = 9\)

\({p \over 7 p} = {1 \over 7}\)

\({6 a \over 15 a} = \frac{2}{5}\)

\({-27 a \over -3 a} = 9\)

\({-8 x y \over -20 x z} = {2 y \over 5 z}\)

\({-12 b \over 28 a b} = -{3 \over 7 a}\)

\({-40 x y z \over 5 y z} = -8 x\)

\({7 x y \over y} + {2 x z \over z} = 7 x + 2 x = 9 x\)

\(3 p - {9 \over 8 p} = {3 p \over 1} ⋅ {8 p \over 8 p} - {9 \over 8 p} = {24 p^{2} \over 8 p} - {9 \over 8 p} = {24 p^{2} - 9 \over 8 p}\)

\({7 b \over 3 a} + {5 a \over 9 b} = {21 b^{2} \over 9 a b} + {5 a^{2} \over 9 a b} = {5 a^{2} + 21 b^{2} \over 9 a b}\)

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

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

\(-{1 \over 7} ⋅ a = -{a \over 7}\)

\({9 b \over a} ⋅ {a - 3 \over 4} = {9 b (a - 3) \over 4 a} = {9 a b - 27 b \over 4 a}\)

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

\(-{4 \over 9} : a = -{4 \over 9} : {a \over 1} = -{4 \over 9} ⋅ {1 \over a} = -{4 \over 9 a}\)

\(-{5 \over 8} : {x - 2 y \over y} = -{5 \over 8} ⋅ {y \over x - 2 y} = -{5 y \over 8 (x - 2 y)} = -{5 y \over 8 x - 16 y}\)

\({7 x \over 9} + {x - 3 \over 4} = {28 x \over 36} + {9 (x - 3) \over 36} = {28 x + 9 (x - 3) \over 36} = {37 x - 27 \over 36}\)

\({3 a + 2 \over 8 a + 9} - 5 = {3 a + 2 \over 8 a + 9} - {5 (8 a + 9) \over 8 a + 9} = {3 a + 2 - 5 (8 a + 9) \over 8 a + 9} = {3 a + 2 - 40 a - 45 \over 8 a + 9} = {-37 a - 43 \over 8 a + 9}\)