What is the equation in point-slope form of the line passing through (1, 9) and (-1, 11)?
y + 9 = -(x - 1)
y - 9 = 1(x + 1)
y + 9 = 1(x + 1)
y - 9 = -(x - 1)

Solution:

The equation of point-slope form is used to find the equation of a line when we know the slope of the line and a point on the line are known.

Point slope formula: y - y₁ = m (x - x₁) ----------- (1)

⇒ m = slope (x1, y1) 

To begin, we must use the slope formula to determine the slope: y₂ - y₁/ x₂ - x₁ = Slope

Given two coordinates, solve for:

(1, 9) and (-1, 11)

Fill in the values in the slope formula:

⇒ Slope = 11 - 9 / -1 -1

⇒ 2 / -2 = -1

Now we know that: 

m = -1 and the (x₁, y₁) would be (1, 9)

Put the values in equation (1), we get

(y - 9) = -1(x - 1).

The equation in point-slope form of the line passing through (1, 9) and (-1, 11) is y - 9 = -(x - 1).

---

What is the equation in point-slope form of the line passing through (1, 9) and (-1, 11)?

Summary:

The equation in point-slope form of the line passing through (1, 9) and (-1, 11) is (y - 9) = -(x - 1).