Factorise- 84 - 2r - 2r-2- - Maths Q - A

Factorize the polynomial84 2r 2r^20ex0ex= 2r^2 2r+840ex0ex= 2(r^2+r 42)0ex0ex= 2(r^2+7r 6r 42)0ex0ex= 2[r(r+7) 6(r+7)]0ex0ex= 2(r 6)(r+7)0ex0ex=2(6 r)(r+7)Hence ...

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Standard X

Mathematics

Division Algorithm for a Polynomial

Factorise: 84...

Question

Factorise: $84 - 2 r - 2 r^{2}$ .

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Solution

Factorize the polynomial
$84 - 2 r - 2 r^{2} = - 2 r^{2} - 2 r + 84 = - 2 (r^{2} + r - 42) = - 2 (r^{2} + 7 r - 6 r - 42) = - 2 [r (r + 7) - 6 (r + 7)] = - 2 (r - 6) (r + 7) = 2 (6 - r) (r + 7)$
Hence, the factors of $84 - 2 r - 2 r^{2}$ are $2, (6 - r)$ and $(r + 7)$ .

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Similar questions

Q. Question 23
Factorise
(i)

x^{2} + 9 x + 18

(ii)

6 x^{2} + 7 x - 3

(iii)

2 x^{2} - 7 x - 15

(iv)

84 - 2 r - 2 r^{2}

Q. Factorise:
49a² + 84ab + 36b²

Q. Factorise :

84 - 2 r - 2 r^{2}

Q. Question 23
Factorise
(i)

x^{2} + 9 x + 18

(ii)

6 x^{2} + 7 x - 3

(iii)

2 x^{2} - 7 x - 15

(iv)

84 - 2 r - 2 r^{2}

Q. factorise the following(middle term splitting)
i)6x^2+7x-3
ii)84-2r-2r^2

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Factorise: 84-2r-2r2.

Factorize the polynomial84-2r-2r2=-2r2-2r+84=-2r2+r-42=-2(r2+7r-6r-42)=-2rr+7-6(r+7)=-2(r-6)(r+7)=2(6-r)(r+7)Hence, the factors of 84-2r-2r2 are 2,(6-r) and (r+7).

Factorise: $84 - 2 r - 2 r^{2}$ .

Factorize the polynomial
$84 - 2 r - 2 r^{2} = - 2 r^{2} - 2 r + 84 = - 2 (r^{2} + r - 42) = - 2 (r^{2} + 7 r - 6 r - 42) = - 2 [r (r + 7) - 6 (r + 7)] = - 2 (r - 6) (r + 7) = 2 (6 - r) (r + 7)$
Hence, the factors of $84 - 2 r - 2 r^{2}$ are $2, (6 - r)$ and $(r + 7)$ .