The scalar product, or dot product, of two vectors is the sum of the products of corresponding coordinates.
... u·v = (4, 4)·(-8, 3) = 4(-8) + 4(3) = -20
Then the product of a scalar and a vector is a vector with each of the original coordinates multiplied by the scalar.
... (u·v)v = -20v = -20(-8, 3) = (160, -60)
