Răspuns:
a) (x√2+1)(x√2-1)=2x²-1
b) (a√10-4)(a√10+4)=10a²-16
c) (x√3+7x)(x√3-7x)=3x²-49x²=-46x²
d) (a√7+a√6)(a√7-a√6)=7a²-6a²=a²
e) (y√13+y√3)(y√13-y√3)=13y²-3y²=10y²
f) (4x-x√6)(4x+x√6)=16x²-6x²=10x²
