To find the equation in slope-intercept form \(y = mx + b\) using the points (5, -5) and (1, 5), we'll follow these steps:
- Calculate the slope (m) using the formula:
\[ m = \frac{y_2 - y_1}{x_2 - x_1} \]
Using the points (5, -5) as \((x_1, y_1)\) and (1, 5) as \((x_2, y_2)\):
\[ m = \frac{5 - (-5)}{1 - 5} = \frac{5 + 5}{1 - 5} = \frac{10}{-4} = -\frac{5}{2} \]
- Use one of the points to find the y-intercept (b). We can use the point (5, -5) and the slope we just calculated:
\[ y = mx + b \implies -5 = -\frac{5}{2}(5) + b \] \[ -5 = -\frac{25}{2} + b \] \[ b = -5 + \frac{25}{2} \] \[ b = -\frac{10}{2} + \frac{25}{2} = \frac{15}{2} \]
- Write the equation in slope-intercept form:
Now that we have both the slope \(m = -\frac{5}{2}\) and the y-intercept \(b = \frac{15}{2}\), we can write the equation:
\[ y = -\frac{5}{2}x + \frac{15}{2} \]
This is the equation of the line in slope-intercept form.