\({3 \over 8 a} - {2 \over 8 a} = {1 \over 8 a}\)

\({3 \over x} - {9 \over 6 x} = {18 \over 6 x} - {9 \over 6 x} = {9 \over 6 x} = {3 \over 2 x}\)

\({6 \over 7 x} - {2 \over 5 y} = {30 y \over 35 x y} - {14 x \over 35 x y} = {30 y - 14 x \over 35 x y}\)

\(7 + {8 \over 9 p} = {7 \over 1} + {8 \over 9 p} = {63 p \over 9 p} + {8 \over 9 p} = {63 p + 8 \over 9 p}\)

\(4 a - {7 \over 2 a} = {4 a \over 1} ⋅ {2 a \over 2 a} - {7 \over 2 a} = {8 a^{2} \over 2 a} - {7 \over 2 a} = {8 a^{2} - 7 \over 2 a}\)

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

\({9 b \over 6 a} + {5 a \over 2 b} = {9 b^{2} \over 6 a b} + {15 a^{2} \over 6 a b} = {15 a^{2} + 9 b^{2} \over 6 a b} = {5 a^{2} + 3 b^{2} \over 2 a b}\)

\({3 x \over x} = {3 \over 1} = 3\)

\({a \over 3 a} = {1 \over 3}\)

\({10 x \over -45 x} = -\frac{2}{9}\)

\({-15 a \over -3 a} = 5\)

\({-12 x y \over 15 x z} = -{4 y \over 5 z}\)

\({-20 q \over 25 p q} = -{4 \over 5 p}\)

\({12 a b c \over 3 b c} = 4 a\)

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

\({3 \over x} ⋅ -{7 \over y} = -{21 \over x y}\)

\({x \over 8} ⋅ {5 \over y} = {5 x \over 8 y}\)

\({1 \over 8} ⋅ a = {a \over 8}\)

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

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