Let x represent the width of the garden(s). Then the length of the second garden is (3x+3). The area is the product of length and width,
90 = x(3x+3)
30 = x(x+1)
At this point, you can recognize that 5 and 6 are factors of 30 that will satisfy this equation, or you can solve the quadratic
x² +x -30 = 0
(x +6)(x -5) = 0
x = 5 . . . . . . . the negative solution does not apply
The width of the garden is 5 m.
