1)
у=2х-1
3х+2(2х-1)=12
3х+4х-2=12
7х=14
х=2
у=2×2-1=3
(2;3)
2)
4-4с+с^2-с^2-4с=4-8с=4-8×0.5=0
5)
у=3х-2
х^2-4х+8=3х-2
х^2-4х+8-3х+2=0
х^2-7х+10=0
д=49-4×10=9
х1=(7-3)/2=2
х2=(7+3)/2=5
у1=3×2-2=4
у2=3×5-2=13
(2;4)(5;13)
6<10 -2<2
-17<-13 -6<-2
9>-3 -15<5
a) <
б)<
B)>
3)c a b
B⁴ + b³ - b - 1 = (b⁴ + b³) - (b + 1) =b³(b + 1) - (b + 1) = (b + 1)(b³ - 1) =
= ( b + 1)(b - 1)(b² + b + 1)