<span>1) 4+2m+2n+mn =2(2+m)+n(2+m)=(2+n)(2+m)
</span><span>2) rt+t-2r-2=t(r+1)-2(r+1)=(t-2)(r+1)
</span><span>3)am+an+4m+4n=a(m+n)+4(m+n)=(a+4)(m+n)
</span><span>4) ab+ac+7b+7c=a(b+c)+7(b+c)=(a+7)(b+c)
</span><span>5) xz+yz-3x-3y=z(x+y)-3(x+y)=(z-3)(x+y)</span>
Решение
a-b=4
a^2-b^2=104 (a-b)(a+b)=104
4*(a+b)=104 a+b=26 a-b=4 a=b+4 a=11+4=15a+b=26 b+4+b=26 2b+4=26 2b=22 b=11 <span>a=15 b=11 </span>
F (x)=4 деленная на cos^2x