7b + 3 - 4b = 3 - 3(b + 4)
3b + 3 = 3 - 3b - 12
3b + 3b = 3 - 12 - 3 = -12
6b = -12
b = -12/6 = -2
b = -2
If we use the width as x we have 2x with both widths and 4x with both lengths. So 6x=24 and x=4. So length is 8 and width is 4.
The third expression is wrong
