i need helpppp for pre algebra

Question

Find the slope from the two points.

(4, 3) (7, 2)

Answer 1

Hi Izzy,

To find the slope from two points there is a "formula" you can use to help:

change in the y-values (rise)

change in the x-values (run)

The ordered pairs are always in the form (x,y). You're going to find the difference in the y-values and that becomes your numerator, then find the difference in your x-values and that becomes your denominator. It doesn't matter which ordered pair you start with BUT the trick is you must go in the same direction both times and watch your signs. If you get a fraction that can be reduced, be sure to simplify.

For this problem, I like to stack my ordered pairs so that I always remember to start with the one I put on top:

(4, 3)

(7, 2)

Using the formula:

3-2 = 1

4-7 = -3 so the slope for this -1/3

*If you did it the other way, remember it won't make a difference (kind of a goof-proof math):

(7, 2)

(4, 3)

2-3 = -1

7-4 = 3 Either way you still get -1/3

Answer 2

Hello, Izzy,

The slope of a line tells us how fast y increases for a change in x. For example, if for x=1, y is 2, and for x=4, y is 8, y changes by 4 every time x increase by 1. The slope is thus 4, or 4/1.

The equation for a straight line can be written as y=mx+b, where m is the slope and b the y-intercept. For the above example, we would have y = 4x + b.

The slope of a straight line can be determined with two points by caculating what is known as the "Rise" over the "Run." The Rise is the change in y for the Run, the change in x.

(4, 3) (7, 2)

The Run is (7-4)=3

The Rise is (2-3) = -1

(I ordered the points by increasing x and then subtracting the first (4,3) from the second (7,2).

The Rise/Run is -1/3

Thus, the slope is -(1/3)

I hope this helps,

Bob

Answer 3

3-2 divided by 4-7 = 1/-3 =-1/3