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

\({9 \over a} - {3 \over 5 a} = {45 \over 5 a} - {3 \over 5 a} = {42 \over 5 a}\)

\({5 \over 3 x} + {6 \over 7 y} = {35 y \over 21 x y} + {18 x \over 21 x y} = {35 y + 18 x \over 21 x y}\)

\(3 - {9 \over 4 x} = {3 \over 1} - {9 \over 4 x} = {12 x \over 4 x} - {9 \over 4 x} = {12 x - 9 \over 4 x}\)

\({4 p \over q} + {9 \over 3 q} = {12 p \over 3 q} + {9 \over 3 q} = {12 p + 9 \over 3 q} = {4 p + 3 \over q}\)

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

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

\({-12 a \over 20 a} = -\frac{3}{5}\)

\({9 a \over 3 a} = 3\)

\({-10 x y \over -25 x z} = {2 y \over 5 z}\)

\({-6 y \over -16 x y} = {3 \over 8 x}\)

\({-16 x y z \over -4 y z} = 4 x\)

\({2 a b \over b} + {7 a c \over c} = 2 a + 7 a = 9 a\)

\(4 a + {3 \over 8 a} = {4 a \over 1} ⋅ {8 a \over 8 a} + {3 \over 8 a} = {32 a^{2} \over 8 a} + {3 \over 8 a} = {32 a^{2} + 3 \over 8 a}\)

\({5 y \over 8 x} + {9 x \over 7 y} = {35 y^{2} \over 56 x y} + {72 x^{2} \over 56 x y} = {72 x^{2} + 35 y^{2} \over 56 x y}\)

\({2 \over x} ⋅ -{8 \over y} = -{16 \over x y}\)

\({a \over 4} ⋅ {7 \over b} = {7 a \over 4 b}\)

\(-{8 \over 5} ⋅ p = -{8 p \over 5}\)

\({3 y \over x} ⋅ {x + 8 \over 2} = {3 y (x + 8) \over 2 x} = {3 x y + 24 y \over 2 x}\)

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

\(-{2 \over 5} : a = -{2 \over 5} : {a \over 1} = -{2 \over 5} ⋅ {1 \over a} = -{2 \over 5 a}\)

\({1 \over 3} : {x + 9 y \over y} = {1 \over 3} ⋅ {y \over x + 9 y} = {y \over 3 (x + 9 y)} = {y \over 3 x + 27 y}\)

\({9 p \over 4} + {p + 3 \over 5} = {45 p \over 20} + {4 (p + 3) \over 20} = {45 p + 4 (p + 3) \over 20} = {49 p + 12 \over 20}\)

\({-9 x + 3 \over 7 x + 1} - 8 = {-9 x + 3 \over 7 x + 1} - {8 (7 x + 1) \over 7 x + 1} = {-9 x + 3 - 8 (7 x + 1) \over 7 x + 1} = {-9 x + 3 - 56 x - 8 \over 7 x + 1} = {-65 x - 5 \over 7 x + 1}\)

\({6 a^{2} - 3 a + 90 \over 3 a} = {6 a^{2} \over 3 a} - {3 a \over 3 a} + {90 \over 3 a} = 2 a - 1 + {30 \over a}\)

\({5 x^{2} - 3 x + 7 \over 2 x^{2}} = {5 x^{2} \over 2 x^{2}} - {3 x \over 2 x^{2}} + {7 \over 2 x^{2}} = 2\frac{1}{2} - {3 \over 2 x} + {7 \over 2 x^{2}}\)