a) -2t + 5 + 8t + 3 - 7t + 13 dla t = -1
-2*(-1) + 5 + 8*(-1) + 3 - 7*(-1) + 13 = 2 + 5 - 8 + 3 + 7 + 13 = 22
b) [tex]2\frac{1}{2}x - 9y + 4x + 3y - \frac{1}{2}x[/tex] dla x = -2 i [tex]y = \frac{1}{3}[/tex]
[tex]\frac{5}{3}*(-2) - 9*\frac{1}{3} + 4*(-2) + 3*\frac{1}{3} - \frac{1}{2}*(-2) = -\frac{10}{3} - 3 - 8 + 1 + 1 = -\frac{10}{3} - 9 = -\frac{10}{3} + \frac{27}{3} = - \frac{37}{3} = -12\frac{1}{3}[/tex]
c) -7t + 3 + 9t - 1 - 3t + 17 dla t = -1
-7*(-1) + 3 + 9*(-1) - 1 - 3*(-1) + 17 = 7 + 3 - 9 + 1 + 3 + 17 = 20
