Respuesta :

We have an equation:
3x+By=-1

We have to find the value of "B".
If passes through the point (2,7) when x=2; "y" must be "7"; therefore:
3(2)+B(7)=-1
6+7B=-1
7B=-1-6
7B=-7
B=-7/7
B=-1

answer: The value of  coefficient "B" will be "-1".