Question

F(x)=ax^2+bx-2
Calculate a and b such that
F (I) = 5 and F (-2)=20​

Answer 1

a=6 , b=1

If F(1)=5 then we have 5= a + b -2
If F(-2)=20 then 22= 4a -2b
If we simplify the second one : 11=2a -b
Then by adding these two we have 3a=18, so a=6 and b=1