B8 . , , . :
- x0 f(x), : f(x0) ≥ f(x).
- x0 f(x), : f(x0) ≤ f(x).
, :
- , . , . .
- . x0 , f(x0) ≠ 0, : f(x0) ≥ 0 f(x0) ≤ 0. : OX, f(x) ≥ 0. , OX, f(x) ≤ 0.
- . , , . , , . .
B8 .
- . f(x), [−5; 5]. f(x) .
. [−5; 5] x = −3 x = 2,5. :
, x = −3 . .
: −3
- . f(x), [−3; 7]. f(x) .
. , [−3; 7] x = −1,7 x = 5. . :
, x = 5 .
: 5
- . f(x), [−6; 4]. f(x), [−4; 3].
. , , [−4; 3]. , [−4; 3] . , x = −3,5 x = 2. :
x = 2. .
: 1
. , x = −3,5, x = −3,4. , , . , .