\({4 \over 9 x} - {7 \over 9 x} = -{3 \over 9 x} = -{1 \over 3 x}\)

\({7 \over p} + {8 \over 3 p} = {21 \over 3 p} + {8 \over 3 p} = {29 \over 3 p}\)

\({3 \over 8 a} + {6 \over 7 b} = {21 b \over 56 a b} + {48 a \over 56 a b} = {21 b + 48 a \over 56 a b}\)

\(7 + {8 \over 5 a} = {7 \over 1} + {8 \over 5 a} = {35 a \over 5 a} + {8 \over 5 a} = {35 a + 8 \over 5 a}\)

\({8 x \over y} - {5 \over 4 y} = {32 x \over 4 y} - {5 \over 4 y} = {32 x - 5 \over 4 y}\)

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

\({a \over 8 a} = {1 \over 8}\)

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

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

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

\({-20 y \over 36 x y} = -{5 \over 9 x}\)

\({-45 a b c \over -5 b c} = 9 a\)

\({5 a b \over b} + {2 a c \over c} = 5 a + 2 a = 7 a\)

\(9 a + {7 \over 2 a} = {9 a \over 1} ⋅ {2 a \over 2 a} + {7 \over 2 a} = {18 a^{2} \over 2 a} + {7 \over 2 a} = {18 a^{2} + 7 \over 2 a}\)

\({3 b \over 7 a} + {2 a \over 8 b} = {24 b^{2} \over 56 a b} + {14 a^{2} \over 56 a b} = {14 a^{2} + 24 b^{2} \over 56 a b} = {7 a^{2} + 12 b^{2} \over 28 a b}\)

\({9 \over p} ⋅ {7 \over q} = {63 \over p q}\)

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

\(-{4 \over 9} ⋅ x = -{4 x \over 9}\)

\({5 y \over x} ⋅ {x - 4 \over 3} = {5 y (x - 4) \over 3 x} = {5 x y - 20 y \over 3 x}\)

\({8 \over a} : {3 \over b} = {8 \over a} ⋅ {b \over 3} = {8 b \over 3 a}\)

\(-{4 \over 7} : p = -{4 \over 7} : {p \over 1} = -{4 \over 7} ⋅ {1 \over p} = -{4 \over 7 p}\)

\({7 \over 4} : {a + 2 b \over b} = {7 \over 4} ⋅ {b \over a + 2 b} = {7 b \over 4 (a + 2 b)} = {7 b \over 4 a + 8 b}\)

\({9 x \over 5} + {x - 4 \over 7} = {63 x \over 35} + {5 (x - 4) \over 35} = {63 x + 5 (x - 4) \over 35} = {68 x - 20 \over 35}\)

\({-4 x - 2 \over -9 x + 6} - 3 = {-4 x - 2 \over -9 x + 6} + {-3 (-9 x + 6) \over -9 x + 6} = {-4 x - 2 - 3 (-9 x + 6) \over -9 x + 6} = {-4 x - 2 + 27 x - 18 \over -9 x + 6} = {23 x - 20 \over -9 x + 6}\)

\({2 a^{2} + 4 a - 60 \over 2 a} = {2 a^{2} \over 2 a} + {4 a \over 2 a} - {60 \over 2 a} = a + 2 - {30 \over a}\)

\({9 x^{2} + 7 x + 1 \over 2 x^{2}} = {9 x^{2} \over 2 x^{2}} + {7 x \over 2 x^{2}} + {1 \over 2 x^{2}} = 4\frac{1}{2} + {7 \over 2 x} + {1 \over 2 x^{2}}\)