9u means you're multiplying 9 into that vector, both components. Same with the 2v. 9*3 = 27 and 9*-1 = -9, so your new vector u is <27, -9>. Now let's do v. 2* -6 (twice) = -12, so your new v vector is <-12, -12>. Add those together now, first components of each and second components of each. 27 + (-12) = 15; -9+(-12)=-21. So the addition of those gives us a final vector with a displacement of <15, -21>
It'll be 4^2+ 3^2 then the answer you get you take the square root of it which will give you the hypotenuse.
Your answer would be 5 because square root of 25 is 5
If u want the formula it's a^2+b^=c^2
C is the hypotenuse and a and b is the lengths
B... juss combine like terms