Question

Check whether 7 + 3x is a factor of (3x³ + 7x).

Answer 1

Apply remainder theorem
=>7 + 3x =0
=> 3x = - 7
=> x = - 7/3
Replace x by - 7/3 we get
=>3x3 + 7x
=>3(-7/3)3 + 7(-7/3)
=>3(-343/27) – 49/3
=> (-343/9) – 49/3
This value is not equal to 0
we have checked that 7 + 3x is not a factor of expression 3x3 + 7x

Answer 2

here is your answer .
I hope it will work.