Oi
Just calculating the differential. Step by step:

If you want to know where the tangent has no slope:
The correct answer is A and B because if you replace the m's with 4 than you do get the answer at the end of the equation. Hope this helps.
Answer is
U= (-2,2)
V=(-2,4)
W= (-4,3)
Step by step
Find points for the triangle.
Using the rule for reflection across y axis.
The rule for a reflection over the y -axis is (x,y)→(−x,y)
U (2,2) ➡️ (-2,2)
V (2,4) ➡️ (-2,4)
W (4,3) ➡️ (-4,3)
2 (-18 - 6) = -48
By order of operations (PEDMAS) the parentheses are calculated first.