Solve for x . Help me

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?

Two times a number plus three times another number equals 4. three times the first number plus four times the other number is 7. find the numbers

We just started the introduction into circles and i have no idea how to do this.