\(\displaystyle{f{{\left({x}\right)}}}={x}^{{2}}+{x}-{12}\)

1. \(\displaystyle\frac{{{f{{\left({b}\right)}}}-{f{{\left({a}\right)}}}}}{{{b}-{a}}}=\frac{{{\left({3}^{{2}}+{3}-{12}\right)}-{\left({0}^{{2}}+{0}-{12}\right)}}}{{{3}-{0}}}\)

\(=4\)

2. \(\displaystyle\frac{{{f{{\left({b}\right)}}}-{f{{\left({a}\right)}}}}}{{{b}-{a}}}=\frac{{{\left({10}^{{2}}+{10}-{12}\right)}-{\left({\left(-{1}\right)}^{{2}}+{\left(-{1}\right)}-{12}\right)}}}{{{10}-{\left(-{1}\right)}}}\)

\(=10\)