I see that you’ve uploaded a math problem image related to circles and equations of lines. Let me transcribe and summarize the key points from the image so I can assist in solving or explaining them.

The questions visible in the image are related to:

6. A diameter of a circle:

• (a) Find an equation of the circle $C_1$, which has endpoints at $(-3, -5)$ and $(7, 3)$.
• (b) Another circle $C_2$ has center $(10, 5)$ and the same radius as $C_1$. Find the equation of the circle $C_2$.
• (c) The two circles intersect at points $R$ and $S$. Show that the equation of the line $RS$ is $y = -2x + 13$.
• (d) Show that the $x$-coordinates of $R$ and $S$ satisfy the equation $5x^2 - 60x + 159 = 0$.

7. The coordinates of two points $A$ and $B$ are $(-7, 3)$ and $(5, 11)$ respectively:

• (a) Show that the equation of the perpendicular bisector of $AB$ is $3x + 2y = 11$.
• (b) A circle passes through $A$ and $B$, and its center lies on the line $12x - 5y = 70$. Find the equation of the circle.

I can now start solving these problems for you step by step. Let me know which part you'd like to begin with, or I can go through all of them!