Final answer:
The slope of the equation -3x + 9y = 4 is 1/3.
Step-by-step explanation:
The equation -3x + 9y = 4 represents a straight line in the coordinate plane. To find the slope of this line, we need to rewrite the equation in slope-intercept form, y = mx + b, where m is the slope.
First, add 3x to both sides of the equation to isolate the y variable: 9y = 3x + 4.
Next, divide both sides of the equation by 9 to solve for y: y = (3/9)x + 4/9.
Since the coefficient of x is 1/3, we can determine that the slope of the line is 1/3. Therefore, the correct answer is b) 1/3.