This is the last piece I need for a proof for a homework problem. Could someone explain whether or not this inequality must hold?

This is the last piece I need for a proof for a homework problem. Could someone explain whether or not this inequality must hold?

$$x_1\overline {x_1}-i\overline{x_1} x_2+ix_1\overline {x_2}+2x_2\overline {x_2}=(ix_1+x_2)\overline{(ix_1+x_2)}+x_2\overline {x_2}=\|ix_1+x_2\|^2+\|x_2\|^2$$