Can someone please help me!!! 100 POINTS!!! Answer ASP, please include an explanation!

Answer:
-39
Step-by-step explanation:
||u|| = sqrt(5² + (-12)²)
= sqrt(25 + 144)
= sqrt(169)
= 13
||cu|| = c ||u||
c = -3
c ||u|| = -3 × 13 = -39
Answer:
-39
Step-by-step explanation:
The magnitude of a vector is given by
|| u|| = sqrt( x^2 + y^2)
= sqrt( 5^2 + (-12)^2)
= sqrt(25+144)
= sqrt(169)
= 13
We are then multiplying by a scalar
||cu|| = -3*13 = -39