Factorize the expressions and divide them as directed.
(i) (y2 + 7y + 10) ÷ (y + 5)
(ii) (m2 -14m - 32) ÷ (m + 2)
(iii) (5p2 - 25p + 20) ÷ (p -1)
(iv) 4yz(z2 + 6z -16) ÷ 2y(z + 8)
(v) 5pq(p2 - q2) ÷ 2p(p + q)
(vi) 12xy(9x2 -16y2) ÷ 4xy(3x + 4y)
(vii) 39y3(50y2 - 98) ÷ 26y2(5y + 7)
Solution:
We will factorize the expressions then cancel out common factors from the numerator and denominator.
(i) (y2 + 7y + 10) ÷ (y + 5)
(y2 + 7y + 10) can be written as ,
y2 + 2 y + 5 y +10 = y(y + 2) + 5(y + 2)
= (y + 2)(y + 5)
Thus, (y2 + 7y + 10) ÷ (y + 5) = (y + 2)(y + 5) / (y + 5)
= y + 2
(ii) (m2 -14m - 32) ÷ (m + 2)
(m2 -14m - 32) can be written as ,
m2 + 2m -16m - 32 = m(m + 2) -16(m + 2)
= (m + 2)(m - 16)
Thus, (m2 -14m - 32) ÷ (m + 2) = (m + 2)(m - 16) / (m + 2)
= m - 16
(iii) (5p2 - 25p + 20) ÷ (p -1)
(5p2 - 25p + 20) can be written as ,
5(p2 - 5p + 4) = 5(p2 - p - 4p + 4)
= 5[p(p - 1) - 4(p - 1)]
= 5(p - 1)(p - 4)
Thus, (5p2 - 25p + 20) ÷ (p - 1) = 5(p - 1)(p - 4) / (p -1)
= 5(p - 4)
(iv) 4yz(z2 + 6z -16) ÷ 2y(z + 8)
4yz(z2 + 6z -16) can be written as ,
4 yz (z2 - 2z + 8z -16) = 4 yz [z(z - 2) + 8(z - 2)]
= 4 yz(z - 2)(z + 8)
Thus, 4yz(z2 + 6z -16) ÷ 2y(z + 8) = 4 yz(z - 2)(z + 8) / 2y(z + 8)
= 2z(z - 2)
(v) 5pq(p2 - q2) ÷ 2p(p + q)
5pq(p2 - q2) can be written as 5pq(p - q)(p + q) [Using identity a2 - b2 = (a + b)(a - b)]
Thus, 5pq(p2 - q2) ÷ 2p(p + q) = 5pq(p - q)(p + q) / 2p(p + q)
= 5q(p - q) / 2
(vi) 12xy(9x2 -16y2) ÷ 4xy(3x + 4y)
12xy(9x2 -16y2) can be written as
12xy[(3x)2 - (4y)2] = 12xy(3x - 4y)(3x + 4y) [Using identity a2 - b2 = (a + b)(a - b)]
= 2 × 2 × 3 × x × y × (3x - 4y) × (3x + 4y)
Thus, 12xy(9x2 -16y2) ÷ 4xy(3x + 4y) = 2 × 2× 3 × x × y × (3x - 4y) × (3x + 4y) / 4xy(3x + 4y)
= 3(3x - 4y)
(vii) 39y3(50y2 - 98) ÷ 26y2(5y + 7)
39y3(50y2 - 98) can be written as
3 × 13 × y × y × y × [2 × (25y2 - 49)] = 3 × 13 × 2 × y × y × y × [(5y)2 - (7)2]
= 3 × 13 × 2 × y × y × y(5y - 7)(5y + 7) [Using identity a2 - b2 = (a + b)(a - b)]
Now,
26y2(5y + 7) can be written as 2 × 13 × y × y × (5y + 7)
Thus, 39y3(50y2 - 98) ÷ 26y2(5y + 7) = 3 × 13 × 2 × y × y × y(5y - 7)(5y + 7) / 2 × 13 × y × y × (5y + 7)
= 3y(5y - 7)
☛ Check: NCERT Solutions for Class 8 Maths Chapter 14
Video Solution:
Factorize the expressions and divide them as directed. (i) (y² + 7y + 10) ÷ (y + 5) (ii) (m² -14m - 32) ÷ (m + 2) (iii) (5p² - 25p + 20) ÷ (p -1) (iv) 4yz(z² + 6z -16) ÷ 2y(z + 8) (v) 5pq(p² - q²) ÷ 2p(p + q) (vi) 12xy(9x² -16y²) ÷ 4xy(3x + 4y) (vii) 39y³(50y² - 98) ÷ 26y²(5y + 7)
Class 8 Maths NCERT Solutions Chapter 14 Exercise 14.3 Question 5
Summary:
The following expressions are factorised and divided. (i) (y² + 7y + 10) ÷ (y + 5) (ii) (m² -14m - 32) ÷ (m + 2) (iii) (5p² - 25p + 20) ÷ (p -1) (iv) 4yz(z² + 6z -16) ÷ 2y(z + 8) (v) 5pq(p² - q²) ÷ 2p(p + q) (vi) 12xy(9x² -16y²) ÷ 4xy(3x + 4y) (vii) 39y³(50y² - 98) ÷ 26y²(5y + 7) and the results are (i) y + 2 (ii)m - 16 (iii) 5(p - 4) (iv) 2z(z - 2) (v) 5q(p - q) / 2 (vi) 3(3x - 4y) (vii) 3y(5y - 7)
☛ Related Questions:
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