If $\alpha$ satisfies the equation $x ^ { 2 } + x + 1 = 0$ and $( 1 + \alpha ) ^ { 7 } = \mathrm { A } + \mathrm { B } \alpha + \mathrm { C } \alpha ^ { 2 } , \mathrm {~A} , \mathrm {~B} , \mathrm { C } \geq 0$, then $5 ( 3 \mathrm {~A} - 2 \mathrm {~B} - \mathrm { C } )$ is equal to