13)
=(а-2)(а+2)/2а (а+2)=(а-2)/2а=(0.5-2)/1=-1.5
14)
(а-3)(а+3)/6а (а-3)=(а+3)/6а=(-0.3+3)/-1.8=-1.5
12)
=а (а-4)(а+4)/(а-4)^2=а (а+4)/(а-4)=
=-1×3/-5=3/5
11)
=(а+3)(а-3)/(а+3)^2=(а-3)(а+3)=(12-3)(12+3)=
=9/15=3/5
9)
=(а-6)(а+6)/(а-6)^2=(а+6)/(а-6)=16/4=4
1)
=а^2+6а+9-6а+8а^2=9а^2+9=9×1/9+9=10
2)
=а^2+6а-49+14а-а^2=20а-49=20×(-1/20)-49=
=-50
3)
=16-8а+а^2-а^2-а=16-9а=16-9×(-1/9)=17
4)
=16аб+16а^2-16аб+4б^2=16а^2+4б^2=
=16×14+4×2=224+8=232
5)
=10аб+б^2-10аб+25а^2=б^2+25а^2=
=5+25×10=255
6)
=48а^2+24аб+3б^2-24аб=48а^2+3б^2=
=48×7+3×3=345
7)
=28аб-4а^2-28аб-49б^2=-4а^2-49б^2=
=-4×5-49×2=-20-98=-118