\({3 \over 5 a} + {6 \over 5 a} = {9 \over 5 a}\)

\({9 \over a} + {7 \over 4 a} = {36 \over 4 a} + {7 \over 4 a} = {43 \over 4 a}\)

\({8 \over 5 x} - {9 \over 6 y} = {48 y \over 30 x y} - {45 x \over 30 x y} = {48 y - 45 x \over 30 x y} = {16 y - 15 x \over 10 x y}\)

\(7 - {9 \over 5 p} = {7 \over 1} - {9 \over 5 p} = {35 p \over 5 p} - {9 \over 5 p} = {35 p - 9 \over 5 p}\)

\({2 x \over y} + {9 \over 4 y} = {8 x \over 4 y} + {9 \over 4 y} = {8 x + 9 \over 4 y}\)

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

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

\({-15 a \over 21 a} = -\frac{5}{7}\)

\({-36 p \over 4 p} = -9\)

\({-28 x y \over -32 x z} = {7 y \over 8 z}\)

\({-4 y \over -18 x y} = {2 \over 9 x}\)

\({-35 a b c \over -5 b c} = 7 a\)

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

\(5 p + {9 \over 8 p} = {5 p \over 1} ⋅ {8 p \over 8 p} + {9 \over 8 p} = {40 p^{2} \over 8 p} + {9 \over 8 p} = {40 p^{2} + 9 \over 8 p}\)

\({3 y \over 8 x} + {9 x \over 2 y} = {3 y^{2} \over 8 x y} + {36 x^{2} \over 8 x y} = {36 x^{2} + 3 y^{2} \over 8 x y}\)

\({7 \over a} ⋅ -{6 \over b} = -{42 \over a b}\)

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

\({6 \over 5} ⋅ x = {6 x \over 5}\)

\({6 y \over x} ⋅ {x - 5 \over 9} = {6 y (x - 5) \over 9 x} = {2 y (x - 5) \over 3 x} = {2 x y - 10 y \over 3 x}\)

\({9 \over a} : {3 \over b} = {9 \over a} ⋅ {b \over 3} = {9 b \over 3 a} = {3 b \over a}\)

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

\({4 \over 9} : {p - 5 q \over q} = {4 \over 9} ⋅ {q \over p - 5 q} = {4 q \over 9 (p - 5 q)} = {4 q \over 9 p - 45 q}\)

\({7 x \over 8} + {x - 2 \over 5} = {35 x \over 40} + {8 (x - 2) \over 40} = {35 x + 8 (x - 2) \over 40} = {43 x - 16 \over 40}\)

\({5 a - 7 \over -2 a + 6} + 4 = {5 a - 7 \over -2 a + 6} - {-4 (-2 a + 6) \over -2 a + 6} = {5 a - 7 + 4 (-2 a + 6) \over -2 a + 6} = {5 a - 7 - 8 a + 24 \over -2 a + 6} = {-3 a + 17 \over -2 a + 6}\)