Answer:
a. -4; no
Step-by-step explanation:
Suppose we have two vectors, a and b.
a = (1,2)
b = (2,3)
Their inner product is:
a.b = (1,2).(2,3) = 1*2 + 2*3 = 8
The vectors are perpendicular if their inner product is 0.
In this question:
a = (7,2)
b = (0,-2)
So
a.b = (7,2).(0,-2) = 7*0 + 2*(-2) = -4
-4 is different of 0, so they are not perpendicular.
So the corret answer is:
a. -4; no
