Could someone please confirm if I did this correctly?

Value pre $-$taxWACC$=\frac{E}{E+D}*r_e+\frac{D}{E+D}*r_d$

pre $-$taxWACC$=\frac{E}{E+D}*r_e+\frac{D}{E+D}*r_d$

pre $-$taxWACC$=\frac{69,453\mathrm{.}80}{69,453\mathrm{.}80+1,587\mathrm{.}0}*11\mathrm{.}3\%+\frac{1,587\mathrm{.}0}{69,453\mathrm{.}80+1,587\mathrm{.}0}*2\mathrm{.}4\%=11\mathrm{.}1\%$

pre $-$taxWACC$=\mathrm{.}1104+\mathrm{.}000535=11\mathrm{.}1\%$

$V^U=\frac{\text{F}\text{a}\text{c}\text{e}\text{b}\text{o}\text{o}\text{k}FCFin\text{t}\text{h}\text{e}\text{n}\text{e}\text{x}\text{t}\text{y}\text{e}\text{a}\text{r}}{\text{p}\text{r}\text{e}-\text{t}\text{a}\text{x}\text{W}\text{A}\text{C}\text{C}-\text{g}\text{r}\text{o}\text{w}\text{t}\text{h}\text{r}\text{a}\text{t}\text{e}ofFCFin\text{t}\text{h}\text{e}\text{n}\text{e}\text{x}\text{t}\text{y}\text{e}\text{a}\text{r}}$

$V^U=\frac{396}{11\mathrm{.}02\%-2\%}=4,390\mathrm{.}24$ million

WACC$=\frac{E}{E+D}*r_e+\frac{D}{E+D}*r_d*(1-{}_c)$

WACC$=\frac{69,453\mathrm{.}80}{69,453,80+1,587\mathrm{.}0}*11\mathrm{.}2\%+\frac{1,587\mathrm{.}0}{69,453\mathrm{.}80+1,587\mathrm{.}0}*2\mathrm{.}4\%*(1-40\%)=6\mathrm{.}6\%$

$V^L=\frac{FCF}{\text{W}\text{A}\text{C}\text{C}-g}$

$V^L=\frac{396}{6\mathrm{.}6\%-2\%}=8,608\mathrm{.}70$ million

$PV(ITS)=V^L-V^U$

$PV(ITS)=8,608\mathrm{.}70-4,390\mathrm{.}24=4,218\mathrm{.}46$ million

According to our calculations, the value of Facebook's created interest tax shield is around

$$4,218\mathrm{.}46$ million.of Tax Shield

E$($Equity$)=69\mathrm{.}453\mathrm{.}80-$ value taken from Market values row the WACC table within the ex$\mathrm{.}11$

D$($Debt$)=1,587\mathrm{.}0-$ value taken from Market values row the WACC table within the ex$\mathrm{.}11$

r$\_$E $($Equity$$Cost$$of$$Capital$)=11\mathrm{.}30\%-$ value taken from Cost of Component row the WACC table within ex$\mathrm{.}11$

r$\_$D $($Debt$$Cost$$of$$Capital$)=2\mathrm{.}4\%-$ value taken from Cost of Component row the WACC table

FCF$(2012)=396-$ value taken from FY$2012$E under the Free cash flow to firm section listed under the DCF model within ex$\mathrm{.}11$

g$($Growth$$Rate$$of$$FCF$)=2\%-$ value taken from Terminal Year of Revenue Growth Rate under the Assumptions section of the DCF model within ex$\mathrm{.}11$

$\backslash$tau $\_$c $($Corporate$$Tax$$Rate$)=40\%-$ taken from the assumptions listed under the DCF model within ex$\mathrm{.}11$