\({5 \over 3 a} + {2 \over 3 a} = {7 \over 3 a}\)

\({2 \over x} + {7 \over 4 x} = {8 \over 4 x} + {7 \over 4 x} = {15 \over 4 x}\)

\({6 \over 9 p} - {4 \over 8 q} = {48 q \over 72 p q} - {36 p \over 72 p q} = {48 q - 36 p \over 72 p q} = {4 q - 3 p \over 6 p q}\)

\(5 + {6 \over 7 a} = {5 \over 1} + {6 \over 7 a} = {35 a \over 7 a} + {6 \over 7 a} = {35 a + 6 \over 7 a}\)

\({2 x \over y} + {8 \over 5 y} = {10 x \over 5 y} + {8 \over 5 y} = {10 x + 8 \over 5 y}\)

\({2 p \over p} = {2 \over 1} = 2\)

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

\({8 a \over 20 a} = \frac{2}{5}\)

\({4 x \over -2 x} = -2\)

\({-10 a b \over -15 a c} = {2 b \over 3 c}\)

\({-4 b \over 10 a b} = -{2 \over 5 a}\)

\({16 p q r \over -4 q r} = -4 p\)

\({4 a b \over b} + {2 a c \over c} = 4 a + 2 a = 6 a\)

\(7 p - {2 \over 9 p} = {7 p \over 1} ⋅ {9 p \over 9 p} - {2 \over 9 p} = {63 p^{2} \over 9 p} - {2 \over 9 p} = {63 p^{2} - 2 \over 9 p}\)

\({3 y \over 6 x} - {7 x \over 8 y} = {12 y^{2} \over 24 x y} - {21 x^{2} \over 24 x y} = {-21 x^{2} + 12 y^{2} \over 24 x y} = {-7 x^{2} + 4 y^{2} \over 8 x y}\)

\({9 \over x} ⋅ -{8 \over y} = -{72 \over x y}\)

\({a \over 6} ⋅ -{9 \over b} = -{9 a \over 6 b} = -{3 a \over 2 b}\)

\({8 \over 5} ⋅ a = {8 a \over 5}\)

\({2 y \over x} ⋅ {x + 7 \over 9} = {2 y (x + 7) \over 9 x} = {2 x y + 14 y \over 9 x}\)

\({4 \over a} : {5 \over b} = {4 \over a} ⋅ {b \over 5} = {4 b \over 5 a}\)

\({4 \over 5} : x = {4 \over 5} : {x \over 1} = {4 \over 5} ⋅ {1 \over x} = {4 \over 5 x}\)

\({4 \over 3} : {p + 2 q \over q} = {4 \over 3} ⋅ {q \over p + 2 q} = {4 q \over 3 (p + 2 q)} = {4 q \over 3 p + 6 q}\)

\({8 a \over 3} + {a + 1 \over 5} = {40 a \over 15} + {3 (a + 1) \over 15} = {40 a + 3 (a + 1) \over 15} = {43 a + 3 \over 15}\)

\({-5 a - 9 \over -7 a + 1} + 2 = {-5 a - 9 \over -7 a + 1} - {-2 (-7 a + 1) \over -7 a + 1} = {-5 a - 9 + 2 (-7 a + 1) \over -7 a + 1} = {-5 a - 9 - 14 a + 2 \over -7 a + 1} = {-19 a - 7 \over -7 a + 1}\)