The generic equation for a linear function can be expressed in the slope intercept form f(x) = mx + b, where m is the slope and b is the y intercept. For this problem we can first find the equation of the line. Then we substitute x = 7 to get the f(x) value, which is n at the point x = 7.
To find the equation of the linear function we first find the slope. Slope is defined as the change in f(x) divided by the change in x. As we are given a linear function, the slope at every point is the same. We can pick any two points known to find the slope.
Let's pick (3, 7) and (9, 16). The slope m is m = (16-7)/(9-3) = 9/6 = 3/2.
Now that we have the slope, we can plug in the slope and one of the points to find b. Let's use the point (3, 7).
f(x) = mx + b
7 = (1/2)(3) + b
b = 11/2
Now we can write the equation
f(x) = (1/2)x + 11/2
Plugging in x = 7 we find that f(7) = 9. n = 9
I think the equation is y= -1/3x+1. The slope is going down, so it’s negative. And the y intercept is 1. And how I got a fraction is by using rise/run.
This question would be a lot better if you had actually included the exercises. When a question talks about other questions that you already did, you need to include those too. Otherwise we don't know what the question is talking about. Fortunately I was able to figure it out without seeing the exercises, but just for future reference, you should include that extra information.
When two addends(things you add together) are negative, adding them is a lot like adding positive numbers; you just have a negative sign on the sum. For example,
4 + 5 = 9
-4 + -5 = -9
