A) ab+3a+ba+3b-3a-3b=ab+ba=ab+ab=2ab
б) 2x-2y+6y-6x-4x-4y= -8x+4y-4y= -8x
в) ab+ac-ba-bc-ca-cb= -bc-cb= -2bc
г) mn-mt+nt-nm+m-n=nt-mt+m-n
<span>X=4 x=9
+ _ +
————(4)————-(9)—————
x(-;4) U (9;)</span><span>(х-4)(х-9)>0;1)х-4>0;х>4. 2)х-9>0;х>9. Вдповдь: (-;4)(9;+)</span>
0,25(√21-5)(√7+3√3)=0,25((√7√3-5)(√7+√3))=0,25(7√3+9√7-5√7-15√3)=
0,25(4√7-8√3)=√7-2√3
2√3+√7-2√3=√7
√7+(2√7-4)/(1+√7)=(√7+7+2√7-4)/(1+√7)=(3√7+3)/(1+√7)=3(√7+1)/(1+√7)=3
^2= у квадраті
4х^2-у^2+6х-3у = (2х-у)*(2х+у)+3(2х-у) = (2х-у)*(2х+у+3)