Verified answer

Ola Alex

f(x) = ax² + bx + c

f(0) = c = 3

f(2) = 4a + 2b = -4

f(5) = 25a + 5b = -1

20a + 10b = -20

50a + 10b = -2

30a = 18

a = 18/30 = 3/5

4a + 2b = -4

12/5 + 2b = -20/5

2b = -32/5

b = -16/5

5a²-2b+c = 4*9/25 + 32/5 + 3

36/25 + 160/25 + 75/25 = 271/25

pronto

Aqui basta resolver o sistema... fica assim a =1, b = -4 e c = 3

então 5a^2 -2b + c = 5 +8 + 3 = 16 pronto!