Verified answer

(4b-9)²-(3b+8)²= (4b-9-3b-8)(4b-9+3b+8)= (b-17)(7b-1)

(3-b)(3+b)(9+b²)+(4+b²)²= (9-b²)(9+b²)+16+8b²+b⁴=81-b⁴+16+8b²+b⁴= 8b²+97

8*1/4+97= 2+97= 99