a) f(x)=x^2+1 => f(-1)=1^2+1=1+1=2;
f( 0) =0^2+1=0+1=1;
f(1) =1^2+1=1+1=2;
f(2) =2^2+1=4+1=5;
b) f(x)=2x+3 =>f(-2) =2*(-2)+3= -1;
f(-1) =2*(-1)+3= +1;
f(0) =2*0+3 = 3;
f(1} =2*1+3=5;
f(2) =2-2+3=7;
c) f(x)=x+2 =>f(-3) = -3+2=-1;
f(-2) = -2+2 =0;
f(-1) = -1+2= 1;
f(0) = 0+2= 1;
f(1) = 1+2=3;