X=width of a coccer pitch 2x-20=length of a soccer pitch Area (rectangule)=length x width We suggest this equation: x(2x-20)=6000 2x²-20x=6000 2x²-20x-6000=0 x²-10x-3000=0 We solve this quadratic equation:
x=[10⁺₋√(100-4*1*-3000)]/2=[10⁺₋√(100+12000)]/2= =(10⁺₋110)/2 we have two solutions: x₁=(10-110)/2=-50, invalid solution. x₂=(10+110)/2=60
x=60 2x-20=2(60)-20=120-20=100
Solution: the length is 100 m, and the width is 60 m.
To check: Area=100 m*60 m=6000 m² The twice of width is =2(60 m)=120 m, 20 m less than twice its width is: 120 m-20 m=100 m=the length.