Just take the function, and wherever it says 'x', substitute '-3' .
Then it'll say f(-3) = -2(-3)² - 7(-3) + 6 . Surely you can solve that.
As my old Electronic Circuits professor used to tell us, back around 1962:
"If
f(x) = -2x² - 7x + 6
then
f(cow) = -2cow² - 7cow + 6 ."
Of all the things I learned from him, this is the thing I remember most.
