a) Aflam intersectia graficului funtiei cu axele de coordonate si stabilim cele doua puncte, prin care reprezentam grafic functia :
[tex]f(x)=5x-2 \\ f(0)=-2; A(0;-2) \\ f(x)=5x-2=0;x= \frac{2}{5} ;B(\frac{2}{5} ;0)[/tex]
b) [tex]f(a)+f(a+1)=f(a-2) \\ 5a-2+5(a+1)-2=5(a-2)-2 \\ 5a-2+5a+5-2=5a-10-2 \\ 5a=-12-1 \\ 5a=-13 \\ a= -\frac{13}{5} [/tex]
c) [tex]f(1)+f(2)+f(3)+...+f(50)= \\ =5*1-2+5*2-2+5*3-2+...+5*50-2= \\ =5*(1+2+3+...+50)-2*50= \\ =5* \frac{50*51}{2} -100=6375-100=6275[/tex]