Question

найдите значение выражения (4+4b+b2)(1/b-2-4/b2-4-1/2b+4), при b=-0.7

Answer 1

1) 1/(b-2))-4/(b-2)(b+2))-1/2(b+2)=(b+2)-4-(b-2))/(b-2)(b+2)=
(b+2-4-b+2)/(b-2)(b+2)=1/(b-2)(b+2)
2) (2+b)^2/(b-2)(b+2)=(2+b)/(b-2)=(2-0.7)/(2+0.7)=1.3/2.7=0.48=0.5