In the solution to this system, what is the value of d?

$\displaystyle{4}{d}-{3}{e}+{2}{f{=}}{4}\usepackage{cmbright}\Huge\$

$\displaystyle-{4}{d}+{5}{e}-{f{=}}-{3}\usepackage{cmbright}\Huge\$

$\displaystyle-{4}{d}+{e}-{6}{f{=}}{4}\usepackage{cmbright}\Huge\$

$\displaystyle{d}=\usepackage{cmbright}\Huge\$ _____