B^2/16b^2:b/36b+81 при b=-9

Question

B^2/16b^2:b/36b+81 при b=-9

Answer 1

B²/16b² : b/(36b+81)=1/16 . 9(4b+9)/b=9(4b+9)/16b, b≠0,b≠-9/4
b=-9 , 9(-36+9)/(-9)=9(-27)/(-9)=27