First you cross multiply.
2*(b-4)=6b
Then distribute the 2.
2b-8=6b
Minus 2b from each side.
-8=4b
Divide each side by 4.
-2=b
So -2 is your answer.
If your solving for x, you need to isolate/get the variable "x" by itself in the inequality:
-24 ≤ 3x - 9 First add 9 on both sides
-24 + 9 ≤ 3x - 9 + 9
-15 ≤ 3x Then divide 3 on both sides to get "x" by itself

-5 ≤ x [or x ≥ -5 if you prefer "x" to be on the left side]
Given:
Length = x + x + 3 = 2x + 3
Width = 2 + x
Area = length * width
91 ft² = (2x + 3) (2+x)
91 = 4x + 2x² + 6 + 3x
0 = 2x² + 7x + 6 - 91
0 = 2x² + 7x - 85
(2x + 17) ( x - 5)
x = -17/2 or x = 5
Let x = 5 ;
length = 2x + 3 = 2(5) + 3 = 13
width = 2 + x = 2 + 5 = 7
Area = 13 x 7 = 91
Perimeter = 2(length + width)
Perimeter = 2(13 + 7)
Perimeter = 2(20)
Perimeter = 20 feet of fencing