*2) new clarendon park is undergoing renovations to is gardens one garden that was a square is being adjusted so that one side is doubled in lien while the ‘ the new rectangular garden will have an area that is more than the original square garden 8. write an equation that could be used to determine the length of a side of the original square garden if ‘ + ) determine the area in square meters of the new rectangular garden

Reading the solution, please, look on the picture) 
Let the side of the square will be X meters. This means that S1=x^2 meters ^2
One side of new rectangular garden will be 2x meters and another (x-3) meters. So S2=2x(x-3) meters ^2
According to the data:
S1*1.25=S2
x^2*1.25=2x(x-3)
1.25*x^2=2x^2-6x
0.75x^2-6x=0
3x^2-24x=0
x^2-8x=0
x(x-8)=0
x=8 or x=0
But x>0!
So x  = 8 meters 

The next question is to find S2.
S2=2x(x-3)=2*8*5=80 meters ^ 2