Question

Question in attachment will give medal

Answer 1

Attachment has answers already.

Answer 2

the one answer in red is incorrect.

Answer 3

you have it nearly right

y = -84 x + b uses the slope from the derivative, correct

at (-7, f(-7)) have

6(-7)^2 -1 = 293 = -84(-7) + b

293 - 588 = b,

you had b>0, but should have b<0, otherwise right, I think.