(9-b)^2-b(b-7) b= -0.8

Question

(9-b)^2-b(b-7) b= -0.8

Answer 1

81-18b+b^2-b^2+7b=81-11b=81-11(-0.8)=81+8.8=89.8

Answer 2

(9-b)²-b(b-7)=81-18b+b²-b²+7b=-11b+81
b= -0.8

-11*(-0.8)+81= 8.8+81=89.8