Answer:
a.b = 62
Step-by-step explanation:
We have a = 8i + 6j and b = 4i + 5j
a.b = (8i + 6j).(4i + 5j) = 8i . 4i + 8i . 5j + 6j . 4i + 6j . 5j = 8 x 4 + 6 x 5 = 32 + 30 = 62
So a.b = 62