Answer:
b=69 degrees
Step-by-step explanation
Use the remote interior angle theorem which states that the sum of the two remote interior angles is equal to the exterior angle. Basically, b=(b-36)+(b-33). That will give you b=2b-69. Then b=69. There's ur answer.
Triangle Area = .5 * base * height
48 = .5 * (x +4) * x
48 = (.5x + 2) * x
48 = .5x^2 + 2x
.5x^2 + 2x -48 = 0
x = 8
base = 12

has gradient

which at the point (-1, 4, 3) has a value of

I'm not sure what the given direction vector is supposed to be, but my best guess is that it's intended to say
, in which case we have

Then the derivative of
at (-1, 4, 3) in the direction of
is

Got your answer.
I drew it out on a digital drawing software I have.
The answer is b)35 because those angles are supplementary which means their sum is 180.
so 180+145 = 35