f(3) = -4*(3)^2 + 3*3 - 5
f(3) = -4*9 + 9 - 5
f(3) = -36 + 4 = -32
f(3+h) = -4*(3+h)^2 + 3*(3+h) - 5
f(3+h) = -4(9 + 6h +h^2) + 9 + 3h - 5
f(3+h) = -36 -24h - 4h^2 + 9 + 3h -5
f(3+h) = -32 -21h -4h^2
Taux de variation [f(3+h)-f(3)] / [(3+h)-(3)]
(-32-21h-4h^2) - (32) / h =
- 4h^2 -21h / h =
- 4h -21
