To find:
The point at which the equation intersects the x-axis.
Solution:
The point at which the equation intersects the x-axis is the x-intercept.
Change the given equation into the intercept form as follows:
[tex]\begin{gathered} 3x+7y=21 \\ \frac{3x}{21}+\frac{7y}{21}=\frac{21}{21} \\ \frac{x}{7}+\frac{y}{3}=1 \end{gathered}[/tex]From the equation, it is clear that the x-intercept is 7. So, the point is (7, 0).
Thus, the answer is (7, 0).