\({6 \over 9 x} + {4 \over 9 x} = {10 \over 9 x}\)

\({2 \over a} - {4 \over 6 a} = {12 \over 6 a} - {4 \over 6 a} = {8 \over 6 a} = {4 \over 3 a}\)

\({9 \over 5 x} + {7 \over 3 y} = {27 y \over 15 x y} + {35 x \over 15 x y} = {27 y + 35 x \over 15 x y}\)

\(8 + {7 \over 4 p} = {8 \over 1} + {7 \over 4 p} = {32 p \over 4 p} + {7 \over 4 p} = {32 p + 7 \over 4 p}\)

\({8 a \over b} - {4 \over 9 b} = {72 a \over 9 b} - {4 \over 9 b} = {72 a - 4 \over 9 b}\)

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

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

\({25 p \over 40 p} = \frac{5}{8}\)

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

\({-15 x y \over 18 x z} = -{5 y \over 6 z}\)

\({6 b \over -8 a b} = -{3 \over 4 a}\)

\({-40 a b c \over 5 b c} = -8 a\)

\({6 x y \over y} + {7 x z \over z} = 6 x + 7 x = 13 x\)

\(3 x - {5 \over 6 x} = {3 x \over 1} ⋅ {6 x \over 6 x} - {5 \over 6 x} = {18 x^{2} \over 6 x} - {5 \over 6 x} = {18 x^{2} - 5 \over 6 x}\)

\({7 b \over 4 a} + {2 a \over 8 b} = {14 b^{2} \over 8 a b} + {2 a^{2} \over 8 a b} = {2 a^{2} + 14 b^{2} \over 8 a b} = {a^{2} + 7 b^{2} \over 4 a b}\)

\({6 \over x} ⋅ {9 \over y} = {54 \over x y}\)

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

\({8 \over 9} ⋅ p = {8 p \over 9}\)

\({2 y \over x} ⋅ {x - 9 \over 3} = {2 y (x - 9) \over 3 x} = {2 x y - 18 y \over 3 x}\)

\({3 \over x} : {8 \over y} = {3 \over x} ⋅ {y \over 8} = {3 y \over 8 x}\)

\({7 \over 5} : a = {7 \over 5} : {a \over 1} = {7 \over 5} ⋅ {1 \over a} = {7 \over 5 a}\)

\(-{5 \over 9} : {a + 6 b \over b} = -{5 \over 9} ⋅ {b \over a + 6 b} = -{5 b \over 9 (a + 6 b)} = -{5 b \over 9 a + 54 b}\)

\({3 p \over 2} + {p + 4 \over 9} = {27 p \over 18} + {2 (p + 4) \over 18} = {27 p + 2 (p + 4) \over 18} = {29 p + 8 \over 18}\)

\({-7 a - 2 \over -3 a - 4} + 9 = {-7 a - 2 \over -3 a - 4} - {-9 (-3 a - 4) \over -3 a - 4} = {-7 a - 2 + 9 (-3 a - 4) \over -3 a - 4} = {-7 a - 2 - 27 a - 36 \over -3 a - 4} = {-34 a - 38 \over -3 a - 4}\)