Find the x and y intercept for f(x)=x^2-3x-40
1 answer:
To find the y-intercept, simply set the value of x equal to 0, and solve for y, or f(x).
f(x) = 0^2 - 3(0) - 40
f(x) = -40
<h3>The y-intercept is -40.</h3>Because this is a 2nd degree polynomial, we cannot find the x-intercepts in one step, and must instead use one of a few different methods.
In this case, we're going to use the quadratic formula:
Plug in the values.
3 +/- √(-3^2 + 160) / 2
3 +/- √169 / 2
3 +/- 13 / 2
(3 + 13) / 2 = 16 / 2 = 8
(3 - 13) = -10 / 2 = -5
<h3>The x intercepts are 8, and -5.</h3>You might be interested in
Look for what 'y' is when t = 1 and t = 2. Go to the graph, look at 1 on the bottom axis and go up till you find the point, then go all the way to the left to see what the y-value is, in this case it should be 1200. If you do the same with t = 2, you will get 2400. So our two ordered pairs are:
(1, 1200), (2, 2400)
We can find the slope of these two points by plugging them into the slope formula:
For points in the form of (x1, y1), (x2, y2). Plug in what we know:
Subtract:
Divide:
This is the slope, so we can write the equation:
(1, 1200), (2, 2400)
We can find the slope of these two points by plugging them into the slope formula:
For points in the form of (x1, y1), (x2, y2). Plug in what we know:
Subtract:
Divide:
This is the slope, so we can write the equation: