Correct. Regroup: $\displaystyle{\left(\frac{{4.2}}{{5.6}}\right)}{\left(\frac{{{10}}^{{-{{12}}}}}{{{10}}^{{6}}}\right)}\usepackage{cmbright}\Huge\$

Divide the numbers: $\displaystyle{\left({0.75}\right)}{\left(\frac{{{10}}^{{-{{12}}}}}{{{10}}^{{6}}}\right)}\usepackage{cmbright}\Huge\$

Use the Quotient Rule: $\displaystyle{0.75}\times{{10}}^{{-{12}-{6}}}={0.75}\times{{10}}^{{-{{18}}}}\usepackage{cmbright}\Huge\$

Convert 0.75 into scientific notation, regroup, and use the product rule: $\displaystyle{7.5}\times{\left({{10}}^{{-{{1}}}}\times{{10}}^{{-{{18}}}}\right)}={7.5}\times{{10}}^{{-{1}+{\left(-{18}\right)}}}={7.5}\times{{10}}^{{-{{19}}}}\usepackage{cmbright}\Huge\$