Factorise

The given 

Polynomial

Asked by shaveta.rishabh | 9th Jul, 2019, 11:35: PM

Expert Answer:

f(y) = y3 - 7y + 6
 
The constant term in f(y) is 6.
 
Factors of 6 = ± 1, ±2, ±3, ±6
 
f(-1) = (-1)3 - 7(-1) + 6 = -1 + 7 + 6 = 12≠ 0
f(1)  = 0  
Therefore by Factor theorem,
(y - 1) is a factor of f(y).
 
Divide f(y) by (y - 1) by using long division method.
 
→ y3 - 7y + 6 = (y - 1)(y2 + y - 6) = (y - 1)(y + 3)(y - 2)

Answered by Yasmeen Khan | 10th Jul, 2019, 10:28: AM