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The length of a rectangle exceeds its breadth by 9 cm. If length and breadth are each increased by 3 cm ,
the area of the new rectangle will be 84 cm^2 more than that of the given rectangle. Find the length and breadth of the given rectangle.
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L and L-9 are the original dimensions.
(L+3) and (L-9)+3 are updated dimensions.
Your equation is
(L+3)*(L-6) = L*(L-9) + 84.
It is a quadratic equation.
Simplify it and solve for L.