Question

Find the volume of cuboid having length, breadth, height are $(5x+3),(5x-3)$ and $(25x^2+9)$ units respectively.

• A. $(625x^4-81)$ ${\text{units}}^3$
  
• B. $(81x^4-625)$ ${\text{units}}^3$
  
• C. $(25x^2-9)$ ${\text{units}}^3$
  
• D. $(25x^4-9)$ ${\text{units}}^3$
  

Answer 1

The correct option is A $(625x^4-81)$ ${\text{units}}^3$


Length of cuboid $=(5x+3)$ units
Breadth of cuboid $=(5x-3)$ units
Height of cuboid $=(25x^2+9)$ units

Volume of cuboid $=\text{length}\times \text{breadth}\times \text{height}$

$\Rightarrow$ Volume $=(5x+3)\times (5x-3)\times (25x^2+9)$

$=\left(\right(5x{)}^2-3^2\left)\right(25x^2+9)$
$=(25x^2-9)(25x^2+9)$
$=\left(\right(25x^2{)}^2-9^2)$
$=(625x^4-81)$ ${\text{units}}^3$

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