multiply

(B+.6) (B-.5)

Using "FOIL" .........

Multiplying the first terms together, we have B*B = B^2

Multiplting the outer terms together, we have  - .5*B = - .5B

And doing the same with the inner terms, we have   .6*B = .6B

And multiplting the last terms together, we have .6*-.5 = -.30

And adding all of these we have

B^2 - .5B + .6B - .30 =

B^2 + .1B - .30