Final answer:
By substituting the given point (1,3) into the equation y = -3x + b, we find the value of b is 6, which corresponds to option A. The slope of the line indicates that it will slope downward to the right.
Step-by-step explanation:
To determine the value of b in the equation y = -3x + b, we can use the given point (1,3) through which the line passes. Substituting x = 1 and y = 3 into the equation:
3 = -3(1) + b
Adding 3 to both sides gives us:
3 + 3 = b
Thus, b = 6. The correct value of b is 6, which corresponds to option A.
If we are to graph the line, we would plot point (1,3) and use the slope m = -3, which indicates that for every one unit increase in x, y decreases by 3 units. This slope means the line will slope downward to the right, as shown in Figure 12.4 part (c).