(4√7-√119-4√3+√51) (4√7+√119+4√3+√51)=

(4√7-√119-4√3+√51) (4√7+√119+4√3+√51)=(4√7-√ (7*17) -4√3+√ (3*17)*(4√7+√ (7*17)+4√3+√ (3*17)=(√7*(4-√17) -√3*(4-√17) (√7*(4+√17)+√3*(4+√17)=(√7-√3) (4-√17) (√7+√3) (4+√17)=(7-3) (16-17)=-4