# The surface area of a cuboidal box is y^2-2y-15.The box has a square base whose length is y+3. Find the height?

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by Georgephilip

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by Georgephilip

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Surface Area of cuboid= 2(y+3)² + 4(y+3)h

From Question we have 2(y+3)²+ 4(y+3) h=y²-2y-15

⇒ (y+3)( 2y+6+4h) = y²+3y -5y -15= y(y+3) -5(y+3)

⇒ (y+3)(2y+6+4h)=(y-5)(y+3)

⇒ 2y+6+4h=y-5

⇒ 4h= -y-11

⇒ h= - (y+11)/4