\({4 \over 8 p} + {9 \over 8 p} = {13 \over 8 p}\)

\({9 \over a} + {4 \over 5 a} = {45 \over 5 a} + {4 \over 5 a} = {49 \over 5 a}\)

\({3 \over 9 a} + {6 \over 2 b} = {6 b \over 18 a b} + {54 a \over 18 a b} = {6 b + 54 a \over 18 a b} = {b + 9 a \over 3 a b}\)

\(7 + {4 \over 3 x} = {7 \over 1} + {4 \over 3 x} = {21 x \over 3 x} + {4 \over 3 x} = {21 x + 4 \over 3 x}\)

\({8 x \over y} + {4 \over 6 y} = {48 x \over 6 y} + {4 \over 6 y} = {48 x + 4 \over 6 y} = {24 x + 2 \over 3 y}\)

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

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

\({-15 x \over -21 x} = \frac{5}{7}\)

\({-18 p \over -3 p} = 6\)

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

\({-4 y \over -14 x y} = {2 \over 7 x}\)

\({-21 a b c \over 3 b c} = -7 a\)

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

\(9 x + {4 \over 5 x} = {9 x \over 1} ⋅ {5 x \over 5 x} + {4 \over 5 x} = {45 x^{2} \over 5 x} + {4 \over 5 x} = {45 x^{2} + 4 \over 5 x}\)

\({8 b \over 3 a} + {4 a \over 7 b} = {56 b^{2} \over 21 a b} + {12 a^{2} \over 21 a b} = {12 a^{2} + 56 b^{2} \over 21 a b}\)

\({5 \over x} ⋅ -{3 \over y} = -{15 \over x y}\)

\({p \over 5} ⋅ -{7 \over q} = -{7 p \over 5 q}\)

\({4 \over 5} ⋅ a = {4 a \over 5}\)

\({4 y \over x} ⋅ {x - 3 \over 8} = {4 y (x - 3) \over 8 x} = {y (x - 3) \over 2 x} = {x y - 3 y \over 2 x}\)

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

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

\(-{8 \over 5} : {a + b \over b} = -{8 \over 5} ⋅ {b \over a + b} = -{8 b \over 5 (a + b)} = -{8 b \over 5 a + 5 b}\)

\({p \over 8} + {p - 9 \over 7} = {7 p \over 56} + {8 (p - 9) \over 56} = {7 p + 8 (p - 9) \over 56} = {15 p - 72 \over 56}\)