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The rectangular hall shown has area $300\text{ m}^2$, breadth $x$ m and length $(2x+1)$ m. Which quadratic equation represents this situation? 
A$2x^2+x-300=0$
B$x^2+2x-300=0$
C$2x^2-x-300=0$
D$x(2x+1)=300x$
Answer & Solution
Correct answer: A. $2x^2+x-300=0$
From the figure, area $=$ length $\times$ breadth $=x(2x+1)=300$. Expanding gives $2x^2+x=300$, so the required quadratic equation is $2x^2+x-300=0$.
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