The angle between the positive horizontal axis and a given line is 135°. Find the equation of the line if it passes through the point (2,3)

  • A x - y = 1
  • B x + y = 1
  • C x + y = 5
  • D x - y = 5
jamb 1997mathematics

The correct answer is C. x + y = 5

The angle between the positive horizontal axis and a given line is 135°, which means that the slope of the line is tan(135°) = -1.

The point-slope form of the equation of a line is y - y1 = m(x - x1), where m is the slope of the line and (x1, y1) is a point on the line.

Substituting the values for m, x1, and y1, we get y - 3 = -1(x - 2), which simplifies to y - 3 = -x + 2.

Adding x and 3 to both sides, we get x + y = 5. So, the equation of the line is x + y = 5.

Previous question Next question