Answer:
Choice a. [tex]35[/tex]
Step-by-step explanation:
Note that [tex]i=(1,0)[/tex] and [tex]j=(0,1)[/tex], so
[tex]C=2A-B=2(6i-8j)-(-16i+5j)=12i-16j+16i-5j=28i-21j=(28,-21)[/tex]
Now the magnitude of a vector [tex](x,y)[/tex] is [tex]\sqrt{x^2+y^2}[/tex], thus the magnitude of [tex]C[/tex] is
[tex]\sqrt{28^2+(-21)^2}=\sqrt{784+441}=\sqrt{1225}=35[/tex]
