1. Start with the given function: P(x; y) = 5xy - 2y + 3x
2. Substitute \(x = -1\) and \(y = 1\) into the function:
P(-1; 1) = 5(-1)(1) - 2(1) + 3(-1)
3. Calculate each term:
5(-1)(1) = -5
-2(1) = -2
3(-1) = -3
4. Add the results:
-5 - 2 - 3 = -10
5. Thus, the value of the function at \(x = -1\) and \(y = 1\) is:
P(-1; 1) = -10