Slope-intercept form is:
y = mx + b
"m" is the slope, "b" is the y-intercept (the y value when x = 0)
You need to find "m" and "b".
If you look at the graph, at x = 0, y is -1, so the y-intercept is -1.
y = mx - 1
To find the slope, you use the slope formula, and plug in the points (-1,2) and (1,-4):
![m=(y_(2)-y_(1))/(x_(2)-x_(1))](https://img.qammunity.org/2019/formulas/mathematics/middle-school/z0dw2f50sxlfzq2lopgahkmxojiiz6mip4.png)
![m=(-4-2)/(1-(-1))](https://img.qammunity.org/2019/formulas/mathematics/middle-school/hy827pmmkuwr2tjt98vyikbpr866est23p.png)
![m=(-4-2)/(1+1)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/3mfd2twzcwegl6apj4c36w6uqkabhjhotd.png)
![m=(-6)/(2)](https://img.qammunity.org/2019/formulas/mathematics/middle-school/eyuse3pkr33pv792kft4g00k8tl1bgeey8.png)
m = -3
y = -3x - 1 The first choice is your answer