B²-8b+16/2b+6:8²-16/4b+12 при b=2,4

Question

B²-8b+16/2b+6:8²-16/4b+12 при b=2,4

Answer 1

B² -8b +16 =(b -4)²
2b +6 =2(b +3)
b² -16 =(b -4)(b+4)
4b +12 =4(b +3)


(b-4)²/2(b+3) :(b-4)(b+4)/4(b+3) =(b-4)²*4(b+3) /2(b+3)*(b-4)(b+4) =2(b-4)/(b+4) =2(2.4 -4)/(2.4+4) =2*(-1.6) /6.4 = -2/4 = -1/2 = -0.5