A) \[-6\]
B) \[14\]
C) \[20\]
D) \[8\]
Correct Answer: D
Solution :
We have,\[y={{x}^{2}}+ax+b\] \[\Rightarrow \] \[\frac{dy}{dx}=2x+a\] Given, \[\frac{dy}{dx}=0\]at\[x=3\] \[\therefore \] \[2x+a=0\] \[\Rightarrow \] \[a=-2x=-6\] Also, at\[x=3\]and\[y=5\] \[\therefore \] \[9-6(3)+b=5\] \[b=5-9+18=14\] Hence,\[a+b=-6+14=-8\]You need to login to perform this action.
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