Question

(10) For which the value of m, x + 3 is the factor of the polynomial x-2mx + 21 ?​

Answer 1

Answer:

x + 3 is a factor

so x = -3

f(-3) = 0

f(x) = x³-2mx+21

=> f(-3) = (-3)³ - 2m(-3) + 21

=> f(-3) = -27 + 6m + 21

=> f(-3) = 6m - 6

Answer 2

Answer:

The value of m is -3/2

Step-by-step explanation:

the given polynomial:

p(x)=x−2mx+21

(x+3) is the factor of the polynomial p(x)=x−2mx+21

∴p(x)=0

⇒p(−3)=0

⇒−3−2m×(−3)+21=0

⇒−3+6m+21=0

⇒9+6m=0

⇒6m= -9

⇒m= -9/6

∴m= -3/2

Thus ,the value of m is -3/2.