\({2 \over 7 x} + {3 \over 7 x} = {5 \over 7 x}\)

\({8 \over x} + {5 \over 9 x} = {72 \over 9 x} + {5 \over 9 x} = {77 \over 9 x}\)

\({5 \over 7 p} - {3 \over 8 q} = {40 q \over 56 p q} - {21 p \over 56 p q} = {40 q - 21 p \over 56 p q}\)

\(2 - {8 \over 9 a} = {2 \over 1} - {8 \over 9 a} = {18 a \over 9 a} - {8 \over 9 a} = {18 a - 8 \over 9 a}\)

\(6 a + {2 \over 7 a} = {6 a \over 1} ⋅ {7 a \over 7 a} + {2 \over 7 a} = {42 a^{2} \over 7 a} + {2 \over 7 a} = {42 a^{2} + 2 \over 7 a}\)

\({6 a \over b} - {7 \over 5 b} = {30 a \over 5 b} - {7 \over 5 b} = {30 a - 7 \over 5 b}\)

\({5 q \over 9 p} + {6 p \over 3 q} = {5 q^{2} \over 9 p q} + {18 p^{2} \over 9 p q} = {18 p^{2} + 5 q^{2} \over 9 p q}\)

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

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

\({21 x \over 27 x} = \frac{7}{9}\)

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

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

\({9 q \over -24 p q} = -{3 \over 8 p}\)

\({-24 a b c \over -4 b c} = 6 a\)

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

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

\({x \over 6} ⋅ -{7 \over y} = -{7 x \over 6 y}\)

\({8 \over 5} ⋅ a = {8 a \over 5}\)

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

\({6 \over 5} : x = {6 \over 5} : {x \over 1} = {6 \over 5} ⋅ {1 \over x} = {6 \over 5 x}\)

\({x \over 2} + {x + 8 \over 3} = {3 x \over 6} + {2 (x + 8) \over 6} = {3 x + 2 (x + 8) \over 6} = {5 x + 16 \over 6}\)

\({4 x - 1 \over -9 x - 3} - 7 = {4 x - 1 \over -9 x - 3} + {-7 (-9 x - 3) \over -9 x - 3} = {4 x - 1 - 7 (-9 x - 3) \over -9 x - 3} = {4 x - 1 + 63 x + 21 \over -9 x - 3} = {67 x + 20 \over -9 x - 3}\)

\({6 x^{2} + 2 x - 40 \over 2 x} = {6 x^{2} \over 2 x} + {2 x \over 2 x} - {40 \over 2 x} = 3 x + 1 - {20 \over x}\)

\({2 a^{2} + 5 a - 9 \over 4 a^{2}} = {2 a^{2} \over 4 a^{2}} + {5 a \over 4 a^{2}} - {9 \over 4 a^{2}} = \frac{1}{2} + {5 \over 4 a} - {9 \over 4 a^{2}}\)