\({7 \over 4 x} + {6 \over 4 x} = {13 \over 4 x}\)

\({4 \over x} + {5 \over 2 x} = {8 \over 2 x} + {5 \over 2 x} = {13 \over 2 x}\)

\({4 \over 9 p} + {3 \over 7 q} = {28 q \over 63 p q} + {27 p \over 63 p q} = {28 q + 27 p \over 63 p q}\)

\(5 + {2 \over 9 a} = {5 \over 1} + {2 \over 9 a} = {45 a \over 9 a} + {2 \over 9 a} = {45 a + 2 \over 9 a}\)

\({5 a \over b} + {7 \over 2 b} = {10 a \over 2 b} + {7 \over 2 b} = {10 a + 7 \over 2 b}\)

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

\({x \over 9 x} = {1 \over 9}\)

\({-15 a \over 35 a} = -\frac{3}{7}\)

\({10 x \over 2 x} = 5\)

\({-20 a b \over -36 a c} = {5 b \over 9 c}\)

\({-25 y \over -30 x y} = {5 \over 6 x}\)

\({8 p q r \over -2 q r} = -4 p\)

\({6 a b \over b} - {7 a c \over c} = 6 a - 7 a = -a\)

\(2 x + {7 \over 9 x} = {2 x \over 1} ⋅ {9 x \over 9 x} + {7 \over 9 x} = {18 x^{2} \over 9 x} + {7 \over 9 x} = {18 x^{2} + 7 \over 9 x}\)

\({7 b \over 2 a} + {8 a \over 5 b} = {35 b^{2} \over 10 a b} + {16 a^{2} \over 10 a b} = {16 a^{2} + 35 b^{2} \over 10 a b}\)

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

\({x \over 7} ⋅ {5 \over y} = {5 x \over 7 y}\)

\(-{7 \over 4} ⋅ p = -{7 p \over 4}\)

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

\({9 \over x} : {6 \over y} = {9 \over x} ⋅ {y \over 6} = {9 y \over 6 x} = {3 y \over 2 x}\)

\({9 \over 7} : x = {9 \over 7} : {x \over 1} = {9 \over 7} ⋅ {1 \over x} = {9 \over 7 x}\)

\(-{8 \over 7} : {a - b \over b} = -{8 \over 7} ⋅ {b \over a - b} = -{8 b \over 7 (a - b)} = -{8 b \over 7 a - 7 b}\)

\({4 a \over 3} + {a + 6 \over 8} = {32 a \over 24} + {3 (a + 6) \over 24} = {32 a + 3 (a + 6) \over 24} = {35 a + 18 \over 24}\)

\({-3 x - 2 \over 9 x + 8} - 1 = {-3 x - 2 \over 9 x + 8} - {1 (9 x + 8) \over 9 x + 8} = {-3 x - 2 - 1 (9 x + 8) \over 9 x + 8} = {-3 x - 2 - 9 x - 8 \over 9 x + 8} = {-12 x - 10 \over 9 x + 8}\)

\({4 x^{2} + 6 x - 20 \over 2 x} = {4 x^{2} \over 2 x} + {6 x \over 2 x} - {20 \over 2 x} = 2 x + 3 - {10 \over x}\)

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