\({4 \over 7a}+{8 \over 7a}={12 \over 7a}\)

\({3 \over x}-{9 \over 4x}={12 \over 4x}-{9 \over 4x}={3 \over 4x}\)

\({3 \over 7a}-{5 \over 4b}={12b \over 28ab}-{35a \over 28ab}={12b-35a \over 28ab}\)

\(2-{4 \over 9p}={2 \over 1}-{4 \over 9p}={18p \over 9p}-{4 \over 9p}={18p-4 \over 9p}\)

\({3x \over y}+{2 \over 6y}={18x \over 6y}+{2 \over 6y}={18x+2 \over 6y}={9x+1 \over 3y}\)

\({4a \over a}={4 \over 1}=4\)

\({x \over 5x}={1 \over 5}\)

\({10x \over -45x}=-\frac{2}{9}\)

\({35a \over 5a}=7\)

\({4pq \over 14pr}={2q \over 7r}\)

\({15q \over -27pq}=-{5 \over 9p}\)

\({-25abc \over -5bc}=5a\)

\({6ab \over b}+{7ac \over c}=6a+7a=13a\)

\(3x-{8 \over 5x}={3x \over 1}⋅{5x \over 5x}-{8 \over 5x}={15x^2 \over 5x}-{8 \over 5x}={15x^2-8 \over 5x}\)

\({7q \over 8p}+{5p \over 2q}={7q^2 \over 8pq}+{20p^2 \over 8pq}={20p^2+7q^2 \over 8pq}\)

\({9 \over a}⋅{8 \over b}={72 \over ab}\)

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

\({4 \over 9}⋅x={4x \over 9}\)

\({5b \over a}⋅{a+9 \over 3}={5b(a+9) \over 3a}={5ab+45b \over 3a}\)

\({9 \over x}:{4 \over y}={9 \over x}⋅{y \over 4}={9y \over 4x}\)

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

\({6 \over 7}:{p+4q \over q}={6 \over 7}⋅{q \over p+4q}={6q \over 7(p+4q)}={6q \over 7p+28q}\)

\({3a \over 5}+{a+2 \over 7}={21a \over 35}+{5(a+2) \over 35}={21a+5(a+2) \over 35}={26a+10 \over 35}\)

\({7a+1 \over -2a-9}+6={7a+1 \over -2a-9}-{-6(-2a-9) \over -2a-9}={7a+1+6(-2a-9) \over -2a-9}={7a+1-12a-54 \over -2a-9}={-5a-53 \over -2a-9}\)

\({9p^2+3p+60 \over 3p}={9p^2 \over 3p}+{3p \over 3p}+{60 \over 3p}=3p+1+{20 \over p}\)

\({6x^2+7x-5 \over 9x^2}={6x^2 \over 9x^2}+{7x \over 9x^2}-{5 \over 9x^2}=\frac{2}{3}+{7 \over 9x}-{5 \over 9x^2}\)