evaluate the ff.
1. f(x)= x^{4} - x^{3} + x^{2} +x - 1; f(2)
2. f(x)=2 x^{3} - 5x^{2} + 3x + 2; f(-1)
3. f(x)= x^{5} + 7x^{2} - 4x - 13; f(-2)
4. f(x)= x^{3} + 2x^{2} - 3x - 8; f(½)
5. f(x)= 5x^{2} - 4x - 8; f(0.1)