\(\Rightarrow\)f(0)=a.0^2+b
\(\Rightarrow\)f(0)=a.0+b
\(\Rightarrow\)f(0)=0+b=b
mà f(0)=4
\(\Rightarrow\)b=4
f(-3)=a.(-3)^2+b=-14
\(\Rightarrow\)f(-3)=a.9+4=-14
\(\Rightarrow\)a.9=-14-4
\(\Rightarrow\)a.9=-18
\(\Rightarrow\)a=-18:9
\(\Rightarrow\)a=-2
Ta có: f(0)= 4
=> a. 0^2+ b = 4
=> a. 0 + b = 4
=> 0 + b = 4
=> b = 4 - 0
=> b = 4
Ta lại có: f(-3) = -14
=> a. (-3)^2 + b = -14
=> a. 9 + b = -14
=> 9a + 4 = -14 ( vì b = 4 (cmt))
=> 9a = -14 - 4
=> 9a = -18
=> a = -2
Vậy a= -2
b= 4