Х^2-у^2=12
(х-у)(х+у)=12
2*(х+у)=12
х=2+у
2*(2+у+у)=12
4+4у=12
4у=12-4
4у=8
у=2
х=2+2=4
отв. х=4, у=2
Lol kek cheburek xex -............
-3х+1-3х-9=-2(1-х)+2
-6х+1-9=-2+2х+2
-6х-8=2х
-6х=2х+8
-6х-2х=8
-8х=8
х=1
V=S`(t) S=∫1,2v(t)dt=S(2)-S(1)
S(t)=t^2+(8t^3)/3
S(2)=2^2+(8*2^3)/3=4+64/3=76/3
S(1)=1+8/3=11/3
S=76/3-11/3=63/3=21