2к²-3к+4ак-6а=(2к²+4ак)-(3к+6а)=2к(к+2а)-3(к+2а)=(к+2а)(2к-3)
(a+6)(a-1)=a²-a+6a-6=a²++5a-6
(3-9m)(1+3m)=3(1-3m)(1+3m)
=3(1-9m²)
(3n-4m)(2m-n)=6mn-3n²-
-8m²+4mn=10mn-3n²-8m²
7x(x-2y)-(x-y)(7x+y)=
=7х²-14xy-(7х²+xy-7xy-y²)=
=7х²-14xy-7х²+6xy+y²=
=y²-8xy=y(y-8x)
Log2(5x-73)-2=log2(3)
ОДЗ: 5x-73>0; 5x>73; x>14,6
Решение:
log2(5x-73)= log2(3)+2
log2(5x-73)= log2(3)+ log2(4)
log2(5x-73)= log2(12)
5x-73=12
5x=12+73
5x=85
x=17