3
1
а)(25a2-10a+1)+(a2+10a+25)=25a2-10a+1+a2+10a+25=26a2+26
b)(49a2-42a+9)-(4-28a+49a2)=49a2-42a+9-4+28a-49a2=-14a+5
в)-2(16a2-72a-81)=32a2-144a-162
2
a)(9a2-12a+4)+(4a2+12a+9)=9a2-12a+4+4a2+12a+9=13a2+13
b)(16a2-8ab+b2) - (9b2+14ab+16a2)=16a2-8ab+b2-9b2-14ab-16a2=-9b2-22ab+b2
в) -3(49a2-112a-64)=147a2-336a-192