V_1=\int_0^{\frac 14}\int_{-2x}{2x}\int_{(y-2x)e^{2y}}^0dz\,dy\,dx=\int_0^{\frac 14}\int_{-2x}^{2x}(2x-y)e^{2y}dy\,dx=\int_0^{\frac 14}(I(x,2x)-I(x,-2x))\,dx=\int_0^{\frac 14}\frac{e^{4x}-8x}4\,dx=\frac{4e-1}{16}