\({9 \over 4a}-{5 \over 4a}={4 \over 4a}={1 \over a}\)

\({5 \over x}-{4 \over 7x}={35 \over 7x}-{4 \over 7x}={31 \over 7x}\)

\({4 \over 9a}+{3 \over 2b}={8b \over 18ab}+{27a \over 18ab}={8b+27a \over 18ab}\)

\(5+{3 \over 4x}={5 \over 1}+{3 \over 4x}={20x \over 4x}+{3 \over 4x}={20x+3 \over 4x}\)

\({4p \over q}-{8 \over 7q}={28p \over 7q}-{8 \over 7q}={28p-8 \over 7q}\)

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

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

\({-18a \over -21a}=\frac{6}{7}\)

\({24x \over -4x}=-6\)

\({-14xy \over -16xz}={7y \over 8z}\)

\({-12q \over -15pq}={4 \over 5p}\)

\({35xyz \over 5yz}=7x\)

\({5ab \over b}-{6ac \over c}=5a-6a=-a\)

\(5x+{7 \over 6x}={5x \over 1}⋅{6x \over 6x}+{7 \over 6x}={30x^2 \over 6x}+{7 \over 6x}={30x^2+7 \over 6x}\)

\({7b \over 8a}+{4a \over 3b}={21b^2 \over 24ab}+{32a^2 \over 24ab}={32a^2+21b^2 \over 24ab}\)

\({9 \over a}⋅-{6 \over b}=-{54 \over ab}\)

\({p \over 8}⋅-{7 \over q}=-{7p \over 8q}\)

\(-{3 \over 4}⋅x=-{3x \over 4}\)

\({5y \over x}⋅{x-2 \over 9}={5y(x-2) \over 9x}={5xy-10y \over 9x}\)

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

\(-{6 \over 7}:p=-{6 \over 7}:{p \over 1}=-{6 \over 7}⋅{1 \over p}=-{6 \over 7p}\)

\({2 \over 3}:{x-7y \over y}={2 \over 3}⋅{y \over x-7y}={2y \over 3(x-7y)}={2y \over 3x-21y}\)

\({9a \over 4}+{a-2 \over 3}={27a \over 12}+{4(a-2) \over 12}={27a+4(a-2) \over 12}={31a-8 \over 12}\)

\({-7x-9 \over -8x+3}+6={-7x-9 \over -8x+3}-{-6(-8x+3) \over -8x+3}={-7x-9+6(-8x+3) \over -8x+3}={-7x-9-48x+18 \over -8x+3}={-55x+9 \over -8x+3}\)

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

\({5a^2+2a-7 \over 8a^2}={5a^2 \over 8a^2}+{2a \over 8a^2}-{7 \over 8a^2}=\frac{5}{8}+{1 \over 4a}-{7 \over 8a^2}\)