\({5 \over 6 a} + {7 \over 6 a} = {12 \over 6 a} = {2 \over a}\)

\({7 \over x} + {6 \over 8 x} = {56 \over 8 x} + {6 \over 8 x} = {62 \over 8 x} = {31 \over 4 x}\)

\({3 \over 6 p} + {4 \over 2 q} = {3 q \over 6 p q} + {12 p \over 6 p q} = {3 q + 12 p \over 6 p q} = {q + 4 p \over 2 p q}\)

\(4 - {2 \over 5 x} = {4 \over 1} - {2 \over 5 x} = {20 x \over 5 x} - {2 \over 5 x} = {20 x - 2 \over 5 x}\)

\({5 a \over b} - {2 \over 7 b} = {35 a \over 7 b} - {2 \over 7 b} = {35 a - 2 \over 7 b}\)

\({4 a \over a} = {4 \over 1} = 4\)

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

\({8 x \over 18 x} = \frac{4}{9}\)

\({-18 a \over -3 a} = 6\)

\({8 p q \over -18 p r} = -{4 q \over 9 r}\)

\({20 b \over -36 a b} = -{5 \over 9 a}\)

\({-20 x y z \over 5 y z} = -4 x\)

\({5 a b \over b} - {3 a c \over c} = 5 a - 3 a = 2 a\)

\(5 p - {7 \over 9 p} = {5 p \over 1} ⋅ {9 p \over 9 p} - {7 \over 9 p} = {45 p^{2} \over 9 p} - {7 \over 9 p} = {45 p^{2} - 7 \over 9 p}\)

\({9 y \over 3 x} + {8 x \over 5 y} = {45 y^{2} \over 15 x y} + {24 x^{2} \over 15 x y} = {24 x^{2} + 45 y^{2} \over 15 x y} = {8 x^{2} + 15 y^{2} \over 5 x y}\)

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

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

\(-{5 \over 8} ⋅ a = -{5 a \over 8}\)

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

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

\({3 \over 7} : x = {3 \over 7} : {x \over 1} = {3 \over 7} ⋅ {1 \over x} = {3 \over 7 x}\)

\(-{3 \over 8} : {p - 4 q \over q} = -{3 \over 8} ⋅ {q \over p - 4 q} = -{3 q \over 8 (p - 4 q)} = -{3 q \over 8 p - 32 q}\)

\({a \over 6} + {a + 2 \over 5} = {5 a \over 30} + {6 (a + 2) \over 30} = {5 a + 6 (a + 2) \over 30} = {11 a + 12 \over 30}\)