[tex]Zadanie\\\\a)\\\\7a-\frac{1}{2}a\ \ \ dla\ \ \ a=8\\\\7\cdot8-\frac{1}{2}\cdot8=56-4= 52\\\\ b)\\\\3b^2+2b\ \ \ dla\ \ \ b=-4\\\\3\cdot(-4)^2+2\cdot(-4)=3\cdot16-8=48-8= 40\\\\c)\\\\(2x+3y)(5-x)\ \ \ dla\ \ \ x=2\ \ i\ \ y=-3\\\\(2\cdot2+3\cdot(-3))(5-2)=(4-9) \cdot3=-5\cdot3=-15[/tex]
