Question

(3b+1)^2=16

Answer 1

(3b+1) (3b +1) = 16

9b^2 + 3b +3b + 1 = 16

9b^2 + 6b + 1 = 16

9b^2 + 6b + 1 -16 = 16-16

9b^2 + 6b -15 = 0

3(3b^2 + 2b -5) = 0

3(b-1)(3b+5) = 0

b - 1 = 0 3b + 5 = 0
b -1+1 = 0 + 1 3b + 5 - 5 = 0-5
b = 1 3b = -5
3b/3 = -5/3
b = -5/3
b = 1, -5/3

Answer 2

(3b+1)^2=16

3b+1 = ±4

3b+1 = 4
b = 1
or
3b+1 = -4
b = 5/3