Answer:
[tex]L = 6[/tex] --- Length
[tex]W = 4.5[/tex] --- Width
Step-by-step explanation:
Given
Let: [tex]L = Length; W = Width[/tex]
[tex]Area = 27m^2[/tex]
[tex]L = 2W- 3m[/tex]
Required
Find the dimensions of the rectangle
Area (A) is calculated as:
[tex]A = L * W[/tex]
This gives:
[tex]27 = (2W - 3) * W[/tex]
Open bracket
[tex]27 = 2W^2 - 3W[/tex]
Express as a quadratic function
[tex]2W^2 - 3W - 27 = 0[/tex]
Expand
[tex]2W^2 + 6W - 9W - 27 = 0[/tex]
Factorize:
[tex]2W(W + 3) - 9(W + 3) = 0[/tex]
[tex](2W - 9)(W + 3) = 0[/tex]
This gives:
[tex]2W - 9 = 0\ or\ W + 3 = 0[/tex]
[tex]2W = 9 \ or\ W = -3[/tex]
Width can not be negative.
So:
[tex]2W = 9[/tex]
[tex]W = 4.5[/tex]
Recall that:
[tex]L = 2W- 3m[/tex]
[tex]L = 2 * 4.5 - 3[/tex]
[tex]L = 6[/tex]
