Hi! Given $\displaystyle \vec a=<2x,1,1-x>$, $\displaystyle \vec b=<-1,3,0>$ and $\displaystyle \vec c=<5,-1,8>$ as three vectors,find xso that $\displaystyle \vec a$ forms equal angles with the vectors $\displaystyle \vec b$ and $\displaystyle \vec c$.

I tried this $\displaystyle a \cdot b = a \cdot c$ ($\displaystyle \cdot$ is a dot product). Then I isolated $\displaystyle cos\alpha$ and $\displaystyle cos\beta$ and equated them. Then I solved by x. Is this correct?