The graph of the equation 3x + 4y = 15 is a line. The graph of the equation x^2 + y^2 = 9 is a circle. The lines and circle intersect at two points.
To find the coordinates of these points, we can solve the system of equations.
We can do this by first subtracting 3x from both sides of the equation 3x + 4y = 15. This gives us:
4y = 15 - 3x
We can then divide both sides of this equation by 4. This gives us:
y = \frac{15}{4} - \frac{3}{4}x
We can then substitute this equation for y in the equation x^2 + y^2 = 9. This gives us:
x^2 + \left( \frac{15}{4} - \frac{3}{4}x \right)^2 = 9
We can then simplify this equation. This gives us:
x^2 + \frac{225}{16} - \frac{45}{2}x + \frac{9}{16} = 9
We can then combine constant terms on the left-hand side of the equation. This gives us:
x^2 - \frac{45}{2}x + \frac{162}{16} = 0
We can then factor the left-hand side of the equation. This gives us:
\left( x - \frac{27}{4} \right)^2 = 0
We can then take the square root of both sides of the equation. This gives us:
x - \frac{27}{4} = 0
We can then solve for x. This gives us:
x = \frac{27}{4}
We can then substitute this value of x into the equation y = \frac{15}{4} - \frac{3}{4}x to find the y-coordinate of the point of intersection. This gives us:
y = \frac{15}{4} - \frac{3}{4} \cdot \frac{27}{4}
This simplifies to:
y = -\frac{9}{2}
Therefore, the point of intersection of the two graphs is (27/4, -9/2).