\({9 \over 4a}+{7 \over 4a}={16 \over 4a}={4 \over a}\)

\({9 \over x}+{4 \over 7x}={63 \over 7x}+{4 \over 7x}={67 \over 7x}\)

\({8 \over 2p}-{4 \over 5q}={40q \over 10pq}-{8p \over 10pq}={40q-8p \over 10pq}={20q-4p \over 5pq}\)

\(2-{5 \over 7x}={2 \over 1}-{5 \over 7x}={14x \over 7x}-{5 \over 7x}={14x-5 \over 7x}\)

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

\({8a \over a}={8 \over 1}=8\)

\({a \over 6a}={1 \over 6}\)

\({-20x \over -45x}=\frac{4}{9}\)

\({-10p \over -2p}=5\)

\({-18xy \over 21xz}=-{6y \over 7z}\)

\({16y \over -18xy}=-{8 \over 9x}\)

\({28xyz \over -4yz}=-7x\)

\({4ab \over b}-{3ac \over c}=4a-3a=a\)

\(4x+{7 \over 2x}={4x \over 1}⋅{2x \over 2x}+{7 \over 2x}={8x^2 \over 2x}+{7 \over 2x}={8x^2+7 \over 2x}\)

\({4b \over 6a}-{5a \over 9b}={12b^2 \over 18ab}-{10a^2 \over 18ab}={-10a^2+12b^2 \over 18ab}={-5a^2+6b^2 \over 9ab}\)

\({8 \over x}⋅-{3 \over y}=-{24 \over xy}\)

\({a \over 8}⋅-{9 \over b}=-{9a \over 8b}\)

\({3 \over 2}⋅p={3p \over 2}\)

\({3y \over x}⋅{x-4 \over 5}={3y(x-4) \over 5x}={3xy-12y \over 5x}\)

\({9 \over p}:{7 \over q}={9 \over p}⋅{q \over 7}={9q \over 7p}\)

\(-{8 \over 5}:x=-{8 \over 5}:{x \over 1}=-{8 \over 5}⋅{1 \over x}=-{8 \over 5x}\)

\(-{2 \over 7}:{a+9b \over b}=-{2 \over 7}⋅{b \over a+9b}=-{2b \over 7(a+9b)}=-{2b \over 7a+63b}\)

\({5a \over 7}+{a-3 \over 6}={30a \over 42}+{7(a-3) \over 42}={30a+7(a-3) \over 42}={37a-21 \over 42}\)

\({6x-2 \over -8x+9}+5={6x-2 \over -8x+9}-{-5(-8x+9) \over -8x+9}={6x-2+5(-8x+9) \over -8x+9}={6x-2-40x+45 \over -8x+9}={-34x+43 \over -8x+9}\)

\({2x^2-6x+40 \over 2x}={2x^2 \over 2x}-{6x \over 2x}+{40 \over 2x}=x-3+{20 \over x}\)

\({9x^2-4x+3 \over 7x^2}={9x^2 \over 7x^2}-{4x \over 7x^2}+{3 \over 7x^2}=1\frac{2}{7}-{4 \over 7x}+{3 \over 7x^2}\)