Question

What is the equation of the line that passes through the points (-5,5) and has a slope of -1

Answer 1

Answer (assuming it can be in slope-intercept form):

$y = -x$    

Step-by-step explanation:

1) Use the point-slope formula $y-y_1 = m (x-x_1)$ to write the equation of the line in point-slope form. Substitute $m$, $x_1$, and $y_1$ for real values.

Since the $m$ represents the slope, substitute -1 in its place. Since $x_1$ and $y_1$ represent the x and y values of a point the line intersects, use the x and y values of the point (-5,5) for the formula. Substitute -5 for $x_1$ and 5 for $y_1$.

$y-(5) = -1(x-(-5))\\y-5 = -1(x+5)$

2) From the above equation, isolate y to place the equation in slope-intercept form and find the final answer:

$y-5=-1(x+5)\\y-5 = -x -5\\y = -x + 0\\y = -x$