Please help​

Lindsay used two points, (x, y; ) and (+2.82), to find the equation of the line, y = mx + b, that passes through the points. y2-y, first, she used the definition of slope and determined that the value of mis x, - . given this information, which expression must represent the value of b?

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?

:24% of students in a class are girls. if there are less than 30 students in this class, how many students are there? how many girls are there?