PLEASE HELP me with these questions

Two different linear functions are shown below with two points given from each function. use slope-intercept form or point-slope form to find the equation of each. linear function a points: (–5, –2), (–5, 7) linear function b points: (7, –5), (–2, –5) function a has: the equation of line a is: function b has: the equation of line b is:

Which coefficient matrix represents a system of linear equations that has a unique solution ? options in photo*

Acircle has a circumference of 7.850 units. what is its radius?