If r=9, b=5, and g=6. what does (r+b-g)(b-g) equal?

(r+b-g)(b-g)

I this question , we have the values of r,b and g given , which are r=9,b=5,g=6

And we have to find the value of the given expression . And for that we need to substitute the values of r,b and 9 in the expression. That is ,

(9+5-6)(5-6) = 8(-1) = -8

So the value of the given expression is -8.