$b.$ What is NPV assuming the project is financed a of debt?

$NPV=-I_0+{\displaystyle \underset{t=1}{\overset{T}{}}}\frac{E(FC{F}_U)}{(1+\text{W}\text{A}\text{C}\text{C}{)}^t}=311,107$

WACC $=\frac{1}{n}11200\mathrm{.}15\%(1-30\%)=7\mathrm{.}36\%$

${?}_{-}^{-1}{f}^{+}+{}_{L}MRP=5\%+1\mathrm{.}0,6\%=11\mathrm{.}22\%$

${}_L={}_U[1+\frac{D}{E}(1-t)]=0\mathrm{.}698[1+1(1-30\%)]=1\mathrm{.}03$

$7$ can someone explain to me why the firormula applied is not leveraged beta$=$ bbut $+$ bu$*(1+($D$/$E$)*(1-$t$)?$