Question

Check whether 7 + 3x is a factor of 3x3 + 7x,​

Answer 1

apply remainder theorem

7+3x=0

3x= -7 or x= -7/3

replace x= -7/3 in the equation, we get

3x^3+7x=3(-7/3)^3 +7(-7/3)

=3(-343/27)-49/3

=349/9-49/3

this value is not equal to zero then 7+3x is not not a factor of 3x^3+7x