Given the vector a = (x, - 1), B = (2,2), A.B = 0, then 2a-3b =?

Given the vector a = (x, - 1), B = (2,2), A.B = 0, then 2a-3b =?

ab=0
It shows that a ⊥ B, ab = 2x + (- 2) = 0
The solution is x = 1
2a-3b=(2,-2)-(6,6)=(-4,-8)