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

\({4 \over x} - {5 \over 9 x} = {36 \over 9 x} - {5 \over 9 x} = {31 \over 9 x}\)

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

\(2 + {5 \over 7 x} = {2 \over 1} + {5 \over 7 x} = {14 x \over 7 x} + {5 \over 7 x} = {14 x + 5 \over 7 x}\)

\({4 p \over q} + {7 \over 5 q} = {20 p \over 5 q} + {7 \over 5 q} = {20 p + 7 \over 5 q}\)

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

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

\({24 x \over 28 x} = \frac{6}{7}\)

\({12 a \over -3 a} = -4\)

\({-15 p q \over -18 p r} = {5 q \over 6 r}\)

\({-12 b \over 15 a b} = -{4 \over 5 a}\)

\({18 a b c \over 3 b c} = 6 a\)

\({2 p q \over q} + {5 p r \over r} = 2 p + 5 p = 7 p\)

\(3 p - {5 \over 8 p} = {3 p \over 1} ⋅ {8 p \over 8 p} - {5 \over 8 p} = {24 p^{2} \over 8 p} - {5 \over 8 p} = {24 p^{2} - 5 \over 8 p}\)

\({2 b \over 4 a} + {8 a \over 5 b} = {10 b^{2} \over 20 a b} + {32 a^{2} \over 20 a b} = {32 a^{2} + 10 b^{2} \over 20 a b} = {16 a^{2} + 5 b^{2} \over 10 a b}\)

\({9 \over a} ⋅ -{2 \over b} = -{18 \over a b}\)

\({x \over 3} ⋅ {9 \over y} = {9 x \over 3 y} = {3 x \over y}\)

\({9 \over 4} ⋅ x = {9 x \over 4}\)

\({5 y \over x} ⋅ {x - 2 \over 7} = {5 y (x - 2) \over 7 x} = {5 x y - 10 y \over 7 x}\)

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

\(-{2 \over 3} : a = -{2 \over 3} : {a \over 1} = -{2 \over 3} ⋅ {1 \over a} = -{2 \over 3 a}\)

\({5 \over 6} : {x - 7 y \over y} = {5 \over 6} ⋅ {y \over x - 7 y} = {5 y \over 6 (x - 7 y)} = {5 y \over 6 x - 42 y}\)

\({3 a \over 2} + {a + 9 \over 7} = {21 a \over 14} + {2 (a + 9) \over 14} = {21 a + 2 (a + 9) \over 14} = {23 a + 18 \over 14}\)

\({-3 x - 4 \over -6 x + 9} + 5 = {-3 x - 4 \over -6 x + 9} - {-5 (-6 x + 9) \over -6 x + 9} = {-3 x - 4 + 5 (-6 x + 9) \over -6 x + 9} = {-3 x - 4 - 30 x + 45 \over -6 x + 9} = {-33 x + 41 \over -6 x + 9}\)

\({3 a^{2} + 6 a - 90 \over 3 a} = {3 a^{2} \over 3 a} + {6 a \over 3 a} - {90 \over 3 a} = a + 2 - {30 \over a}\)

\({8 a^{2} + 5 a + 3 \over a^{2}} = {8 a^{2} \over a^{2}} + {5 a \over a^{2}} + {3 \over a^{2}} = 8 + {5 \over a} + {3 \over a^{2}}\)