A rational number in its decimal expansion is 0.27575 --------. What can you say about the prime factors of q, when this number is expressed in the form p/q ? Give reasons.
Find the HCF of (6x2+ x –15) and (8x2–32x + 15)

Respuesta :

Answer:

The prime factors of q = 330 are 2, 3, 5 and 11.

HCF of [tex](6x^2+ x -15)[/tex] and [tex](8x^2-32x + 15)[/tex] is 1.

Step-by-step explanation:

First of all, let us convert the given decimal expansion in rational form.

Let Given decimal expansion:

[tex]x =0.27575.....[/tex]

Multiply by 100:

[tex]100x = 27.5757.......[/tex]

subtracting x from 100x :

[tex]99x = 27.5757.... - 0.2757....\\\Rightarrow 99x = 27.3\\\Rightarrow 33x = 9.1\\\Rightarrow x = \dfrac{9.1}{33}\\\Rightarrow x = \dfrac{91}{330}[/tex]

So,

[tex]\dfrac{p}{q} = \dfrac{91}{330}[/tex]

Let us make prime factors of q:

[tex]q = 2 \times 3 \times 5\times 11[/tex]

The prime factors of q = 330 are 2, 3, 5 and 11.

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Finding HCF of [tex](6x^2+ x -15)[/tex] and [tex](8x^2-32x + 15)[/tex]

Method to find HCF:

First of all, let us factorize them and the common part between the factors of the two will be the HCF.

[tex](6x^2+ x -15)\\\Rightarrow 6x^2+ 10x -9x-15\\\Rightarrow 2x(3x+ 5) -3(3x+5)\\\Rightarrow (2x -3)(3x+5)[/tex]

The factors are (2x -3) and (3x+5)

The quadratic equation [tex](8x^2-32x + 15)[/tex] can not be factorized as we have factorized [tex](6x^2+ x -15)[/tex].

[tex]\therefore[/tex] HCF of the two is 1.

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