Răspuns :
1) (√5+a)(√5-a)+3(2-a)=
=√5²-a²+6-3a=
=5-a²+6-3a=
=11-a²-3a
2) (7+x)(7-x)+(2+5)·x=
=7²-x²+7x=49-x²+7x
=√5²-a²+6-3a=
=5-a²+6-3a=
=11-a²-3a
2) (7+x)(7-x)+(2+5)·x=
=7²-x²+7x=49-x²+7x