Given two lines: 3x + y = 1 bx - y = 3 which value of b makes the given lines parallel to each other? -3 3 -2

For lines to be parallel, their slopes should be equal. The equation to determine the slope of the line is -A/B where A and B are the numerical coefficients of terms with variables x and y, respectively. 
                                 -3/1 = -b/-1
The value of b from the equation is -3.