If (x – 6) is a factor of x3
+ ax2
+ bx – b = 0 and a – b = 7, find the values of a and b.
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If (x-6) is a factor of x3+ ax2+bx-b =0 and a-b = 7 find the value of a and b
Posted by Abhishek Raj 3 years, 9 months ago
CBSE > Class 10 > Mathematics
1 answers
Dharmendra Kumar 3 years, 9 months ago
Since (x-6) is a factor of x3+ax2+bx-b=0------(1)
Therefore x=6 is one of the roots of the given cubic polynomial.
So put x=6 in eq.(1) we get,
63+a×62+b×6-b=0
216+36a+6b-b=0
36a+5b=-216 -------(2)
given that a-b=7
a=7+b -----(3)
Substituting the value of a from eq.(3) into eq.(2) we get
36(7+b)+5b=-216
252+36b+5b=-216
41b=-216-252
41b=-468
b=−46841
Substituting this value in eq.(3) we get
a=7+(−46841)=41×7−46841=287−46841=−18141
Answer:
Step-by-step explanation:
Given that x - 6 is a factor of f(x). SO, substitute x =6 in the given polynomial equation
x^3+ax^2+bx-b = 0
put x = 6
6^3 + a (6^2) + 6b - b =0
216 + 36 a + 5b = 0
SO, 36 a + 5b = -216
also, given a - b = 7
so, 5a - 5b = 35
add these both equations
5b is cancelled
41 a = -181
so, a = -181/41 and b = -468/41
I hope it may helpfull to you