Question

A cuboid with a volume of 924cm^3 has dimensions

Answer 1

The values of x are -22 and 10

The dimensions are 4 cm , 11 cm , 21 cm

Step-by-step explanation:

The given is:

• A cuboid with a volume of 924 cm³
• It has dimensions  4 cm , (x + 1) cm and (x + 11) cm

We want to show that x² + 12x - 220 = 0, and solve the equation to find its dimensions

The volume of a cuboid is the product of its three dimensions

∵ The dimensions of the cuboid are 4 , (x + 1) , (x + 11)

∴ Its volume = 4(x + 1)(x + 11)

- Multiply the two brackets and then multiply the product by 4

∵ (x + 1)(x + 11) = (x)(x) +(x)(11) + (1)(x) + (1)(11)

∴ (x + 1)(x + 11) = x² + 11x + x + 11 ⇒ add like terms

∴ (x + 1)(x + 11) = x² + 12x + 11

∴ Its volume = 4(x² + 12x + 11)

∴ Its volume = 4x² + 48x + 44

∵ The volume of the cuboid = 924 cm³

- Equate the expression of the volume by 924

∴ 4x² + 48x + 44 = 924

- Subtract 924 from both sides

∴ 4x² + 48x - 880 = 0

- Simplify it by dividing all terms by 4

∴ x² + 12x - 220 = 0

Now let us factorize it into two factors

∵ x² = x × x

∵ 220 = 22 × 10

∵ 22(x) - 10(x) = 12x ⇒ the middle term

∴ x² + 12x - 220 = (x + 22)(x - 10)

∴ (x + 22)(x - 10) = 0

- Equate each factor by 0 to find x

∵ x + 22 = 0 ⇒ subtract 22 from both sides

∴ x = -22

∵ x - 10 = 0 ⇒ add 10 to both sides

∴ x = 10

∴ The values of x are -22 and 10

We can not use x = -22 because there is no negative dimensions, then we will use x = 10

∵ The dimensions are 4 , (x + 1) , (x + 11)

∵ x = 10

∴ The dimensions are 4 , (10 + 1) , (10 + 11)

∴ The dimensions are 4 cm , 11 cm , 21 cm

Learn more:

You can learn more about the factorization in brainly.com/question/7932185

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