Respuesta :

kdndino

Answer:

a. -4

Step-by-step explanation:

a•b = (x1 × x2) + (y1 × y2)

= (7 × 0) + (2 × -2)

= 0 - 4

= -4

Answer:

Step-by-step explanation:

let a=7i+2j

and b=-2j

a.b=(7i+2j).(0i-2j)

=0i-4j

≠0

they are not perpendicular.

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