Question

(b+2)^3-b(b+3)(b-3)-6b^2=113

Answer 1

b³ + 6b² + 12b + 8 - b³ + 9b - 6b² = 113

9b + 12b - 105 = 0 

21b = 105

b = 105 : 21

b = 5

Answer 2

(b+2)³-b(b+3)(b-3)-6b²=113

(b³+3b²*2+3b*2²+2³)-b(b²-3²)-6b²=113

b³+6b²+12b+8-b³+9b-6b²=113

12b+9b+8=113

21b+8=113

21b=113-8

21b=105

b=105/21=5