Rewrite the equation in slope-intercept form:
9x - 7y = 21
-7y = -9x + 21
y = (9/7)(x) - 3
The y-intercept is where x = 0.
y = (9/7)(0) - 3
y = 0 - 3
y = -3
The x-intercept is where y = 0.
0 = (9/7)(x) - 3
3 = (9/7)(x)
21 = 9x
x = 21/9
x = 7/3
The correct answer would be C. The x-intercept would be at (7/3, 0) and the y-intercept at (0, -3). Hope that helps! :)