Question

Calculati : f(0) + f(1) + ... + f(9) ,unde f:R -> R, f(x)= -x+9

Answer 1

9-1+9-2+9-3+9-4+9-5+9-6+9-7+9-8+9-9+9=8+7+6+5+4+3+2+1+0=36

Answer 2

f(x) = - x + 9
f(0) + f(1) +.......+ f(9) = 9 + 8 + 7 + ......+1 + 0 =  45