Question

If (x+1) is a factor of x³+mx²+19x+12.find the value of m

Answer 1

p(x) = x³+mx²+19x+12
x+1 is the factor so
x+1=0
x= -1

now putting the value of x in above p(x)

we get,

x³+mx²+19x+12 = 0

=>( -1)³+m(-1)²+19(-1)+12= 0
= -1+m-19+12 = 0

= m-20+12= 0

= m-8 = 0

=> m= 8

hope this helps you