Question

check whether 7+3x is a factor of 3x + 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