................. ....................... .............................
-(3х-1)+2(5+х)*(х-5)+7х
-3х-1+10+2х*х-5+7х
-3х+2х*х+7х=-1+10
-1х+7х=-9
-6х=-9
х=1,5
1 + tga / 1 + ctga= (1+sina/cosa)/(1+cosa/sina)=
=((cosa+sina)/cosa)/(cosa(sina+cosa) = sina/cosa=tga
(7b* (a(a-b)/(a-b)*14b=
=a/2
A)2-3x-6=7-2x -3x+2x=7-2+6 -x=11 x=-11