To write the equation of the line in slope-intercept form \(y = mx + b\), we first need to determine the slope \(m\) and the y-intercept \(b\).
Step 1: Find the slope (m)
The slope \(m\) can be calculated using the formula: \[ m = \frac{y_2 - y_1}{x_2 - x_1} \] Using the points A (0, -1) and B (1, 1):
- \(y_1 = -1\), \(x_1 = 0\)
- \(y_2 = 1\), \(x_2 = 1\)
Now plug the values into the formula: \[ m = \frac{1 - (-1)}{1 - 0} = \frac{1 + 1}{1 - 0} = \frac{2}{1} = 2 \]
Step 2: Find the y-intercept (b)
Since point A is at (0, -1), this means that when \(x = 0\), \(y = -1\). Thus, the y-intercept \(b = -1\).
Step 3: Write the equation
Now we have:
- slope \(m = 2\)
- y-intercept \(b = -1\)
Putting it all together, the equation in slope-intercept form is: \[ y = 2x - 1 \]
Final Answer
Therefore, the answer is: \[ y = 2x - 1 \]