Temperature change is not a consideration for this problem. Therefore, the force deformation relationships for each axial member are:

${\mathrm{\delta }}_1=\frac{{\mathrm{F}}_1{\mathrm{L}}_1}{{\mathrm{A}}_1{\mathrm{E}}_1} {\mathrm{\delta }}_2=\frac{{\mathrm{F}}_2{\mathrm{L}}_2}{{\mathrm{A}}_2{\mathrm{E}}_2}$