Answer: C. y= -3x+ 4
Step 1: Write equation in slope- intercept form
To start off, let’s write the formula for slope- intercept form. After we know this, we will continue to substitute information.
y= mx+ b
Step 2: Find y- intercept
Let’s begin by finding the y- intercept. This is the point that falls directly on the y- axis. After we find the y- intercept, we will be able to eliminate two of the options; answer A and C state that the y- intercept is positive 4 and answer B and D say that the y- intercept is negative 4.
Since the line crosses 4 on the y- axis on the top part of the graph, the y- intercept is positive 4. Let’s substitute this into the equation.
y= mx+ b
y= mx+4
Step 3: Find slope
Now that we have updated the equation, let’s find the slope. This will be the final part of the equation. Keep in mind that the only remaining options are A and C, in which the slope is said to be either 3 or -3.
To find the slope, let’s find two points, and use the rise/ run formula. For the sake of this problem, we will use (0,4) and (1,1).
In between these two points, there is a difference of 3/1. This can be reduced to 3; however, since the line on the graph reduces, the slope is negative. This will leave our slope as -3. Let’s put this into our equation.
y= mx+4
y= -3x+4
This is the final equation. Hope this helps! Comment below for more questions.