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#### karush

##### Well-known member

- Jan 31, 2012

- 2,743

well since it mentioned gradient then $f'(x)=2px-q$

then from $A(1,3)$ we have $3=p(1)^2-q(1)$ and from $m=8$, $8=2p(1)-q$

solving simultaneously we have

$3=p-q$

$8=2p-q$

then $p=5$ and $q=2$

thus $f(x)=5x^2-2x$

View attachment 1097

no answer was given on this so just seeing if this is correct