1.
-aba + a²b2ab² + 4 = -a²b + 2a³b³ + 4 = a²b * (- 1 + 2ab²) + 4
a = 2; b = ½
4 * ½ * (-1
+ 2 * 2 * ¼) + 4 = 2 * (- 1 + 1) + 4 = 2
* 0 + 4 = 4
2.
b²5ab – 5a5a²b
= 5ab * (b² – 5a²)
a = 1/5; b = - 2
5 * 1/5 *
(-2) * ((-2)² – 5 * (1/5)²) = - 2 * (4 – 1/5) = - 2 * 19/5 = - 38/5 =
= -
7 3/5 (7 цеых и 3/5)
3.
x²yxy - xy²xy
+ xy = xy * (x²y – xy² + 1)
x = - 3; y
= 2
(- 3) * 2 *
((-3)² * 2 – (-3) * 2² + 1) = - 6 * (9 * 2 + 3 * 4 + 1) = - 6 * (18 + 12 + 1) = - 6 * 31 = - 186
4.
xy²x²y -
xyxy = x²y² * (xy – 1)
x = - 2; y
= 3
(- 2)² *
3² * ((-2) * 3 – 1) = 4 * 9 * (- 6 - 1) = - 36 * 7 = - 252