CBSE Class 9 Answered
Question Factorise: x3 + 13x2 + 32x + 20
Solution:
Let p(x) = x3 + 13x2 + 32x + 20
p(-1) = -1 + 13 - 32 + 20 = -33 + 33 = 0
Therefore (x + 1) is a factor of p(x).
On dividing p(x) by (x + 1) we get
p(x) (x + 1) = x2 + 12x + 20
Thus,
x3 + 13x2 + 32x + 20 = (x + 1)(x2 + 12x + 20)
= (x + 1) (x2 + 10x + 2x + 20)
= (x + 1)[x(x + 10) + 2(x + 10)]
= (x + 1) (x +2) (x + 10)
Hence, x3 + 13x2 + 32x + 20 = (x + 1) (x +2) (x + 10).
The above question is from the sureshot questions but I am not clear with the explanation.Please elaborate.Please reply urgently I have my Maths exam tomorrow
Asked by nayonika.online.learning | 17 May, 2018, 09:08: PM
Expert Answer
Factor theorem is used here
p(x) = x3 + 13x2 + 32x + 20
start by sub x= 1,-1,.... to get p(x)=0
start by sub x= 1,-1,.... to get p(x)=0
now
p(-1) = -1 + 13 - 32 + 20 = -33 + 33 = 0
so x+1 is a factor......factor theorem
now divide x3 + 13x2 + 32x + 20 by x+1......long division
you will get remainder zero, and quotient =x2 + 12x + 20
so,
Divident =divisor x quotient +remainder
x3 + 13x2 + 32x + 20 = (x + 1)(x2 + 12x + 20)......factorize x2 + 12x + 20 by spliting middle term
Answered by Arun | 18 May, 2018, 10:23: AM
Application Videos
-
Algebraic Identities: Quadratic
This video contains a question which is solved using square of binomials -
Factorisation using Square identity
This video explains factorisation using square identity -
Appilcations based problem on Linear Equation in two va ...
This video explains how to form a linear equation using given statements an... -
Application based problem on a Circle -1 ...
This video contains a problem based on the concept of Circle and its Applic... -
Application based problem on a Circle -2 ...
This video contains a question based on the concept of Circle and its Appli...
Concept Videos
-
Rational Numbers ...
Recall the concept of number line and discuss its importance in day to day... -
Irrational Numbers
This video explains how to differentiate between rational and irrational nu... -
Real Numbers
This video covers the definition of real numbers, difference between the ra... -
Laws of Exponents
This video explains the statement of the laws of exponents and simplify exp... -
Introduction to Polynomials
This video explains the definition of polynomial and related terms, identif...
CBSE 9 - Maths
Asked by rathorgaurav2945 | 21 Apr, 2024, 10:31: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by monika.vns14 | 18 Apr, 2024, 05:15: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by gulshanelectronics2017 | 15 Apr, 2024, 05:35: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by tripura78839 | 12 Apr, 2024, 09:05: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by singhanjali0199 | 12 Apr, 2024, 08:29: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by killerstealer593 | 11 Apr, 2024, 07:50: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by saee.shinde3069 | 31 Mar, 2024, 10:12: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by rathoreraj7296 | 31 Mar, 2024, 08:09: PM
ANSWERED BY EXPERTCBSE 9 - Maths
Asked by divyanshibirla037 | 29 Mar, 2024, 03:26: PM
ANSWERED BY EXPERT
