Question 189435
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We know for rectangle,<font color=blue> Area = Length x Width</font>


Given:
Width = <font color=blue>x</font>
Length = <font color=blue>5x-3</font>, 3 meters less than 5 times width
Area = <font color=blue> 36 sq m</font>


Then, 
36 = (5x-3)(x)
36 = 5x^2 - 3x
5x^2 - 3x -36 =0
Remember:{{{system(a=5,b=(-3),c=(-36))}}}
By Quadratic,
Discriminant: {{{b^2-4ac=-3^2-4(5)(-36)=9+720=red(729)}}}
Then,
{{{x=(-(-3)+-sqrt(729))/(2*5)=(3+-27)/10}}}
{{{x=(3+27)/10=30/10=red(3meters)}}}
{{{x=(3-27)/10=-24/10=-2.4}}}, discard


So, Width=<font color=blue>3 meters</font>
Length = 5(3)-3 = 15-3 = <font color=blue>12 meters</font>


Let's check,
A = L x W
36sq m = 12 x 3
36sq.m. = 36 sq. m.


Thank you,
Jojo<font>