हिंदी

Solve the following equation. (3x-4)3-(x+1)3(3x-4)3+(x+1)3=61189 - Algebra

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प्रश्न

Solve the following equation.

`[(3x - 4)^3 - ( x + 1)^3]/[( 3x - 4)^3 + ( x + 1)^3] = 61/189`

योग

उत्तर

`[(3x - 4)^3 - ( x + 1)^3]/[( 3x - 4)^3 + ( x + 1)^3] = 61/189`

Applying componendo and dividendo, we get

`{[(3x - 4)^3 - ( x + 1)^3] + [( 3x - 4)^3 + ( x + 1)^3]} /{[(3x - 4)^3 - ( x + 1)^3] - [( 3x - 4)^3 + ( x + 1)^3]}  = (61 + 189) /(61 - 189)`

⇒ `{2 ( 3x - 4)^3}/{-2( x +1)^3} = 250/-128`

⇒ `{(3x - 4)^3}/( x + 1)^3 = 125/64`

Taking cube root on both sides, we get

`therefore (3x -4)/(x + 1) = root(3)(125/64)`

⇒ `(3x - 4)/(x + 1)= root(3)[(5/4)^3]`

⇒ `(3x - 4)/(x + 1) = 5/4`

⇒ 4(3x - 4) = 5(x + 1)

⇒ 12x - 16 = 5x + 5

⇒ 12x - 5x = 16 + 5

⇒ 7x = 21

⇒ x = 3

Thus, the solution of the given equation is x = 3.

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Application of Properties of Equal Ratios
  क्या इस प्रश्न या उत्तर में कोई त्रुटि है?
अध्याय 4: Ratio and Proportion - Practice Set 4.3 [पृष्ठ ७०]

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बालभारती Algebra (Mathematics 1) [English] 9 Standard Maharashtra State Board
अध्याय 4 Ratio and Proportion
Practice Set 4.3 | Q (4) (vi) | पृष्ठ ७०
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