Evaluate:

xy²(x - 5y) + 1 for x = 2 and y = 1.

xy²(x - 5y) + 1

= x⁽¹⁺¹⁾y² - 5xy⁽²⁺¹⁾ + 1

= x²y² - 5xy³ + 1

For x = 2 and y = 1,

2² x 1² - 5 x 2 x 1³ + 1

= 4 x 1 - 5 x 2 x 1 + 1

= 4 - 10 + 1

= - 5

Hence, for x = 2 and y = 1, the value of [xy²(x - 5y) + 1] is - 5.