Question

Prove if 7x+3x is a factor of 3x³+7x

Answer 1

do you mean 7+3x
if so solution is
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
= -590/9
This value is not equal to 0
so 7 + 3x is not a factor of expression 3x³ + 7x