Question

Which of the following are orthogonal to (2, 1)? Check all that apply.

A. (1, 2)
B. (-2, -3)
C. (-3, 6)
D. (1, -2)

Please explain. Thank you!

Answer 1

have you found the dot products of (2,1) with the others

Answer 2

you want \[a \cdot b=0 \text{ then } a \text{ and } b \text{ are orthogonal }\]