The length of a rectangle is 3cm less than twice its width. The area is 20cm2
Find the dimensions of the rectangle.
please help! highschool quadratic equation word problems
$\displaystyle x(2x-3)=20$ where $\displaystyle x$ is the width of one side.
$\displaystyle 2x^2-3x-20=0 \Rightarrow \ (2x+5)(x-4)=0 \Rightarrow \ x=4, -\frac{5}{2}$.
The length can only be positive so the side is 4cm long.
Therefore one side is 4cm long, the other is 5cm long.