How to write an equation in standard form?

Question

if the problem is:
through (3,7) and (0, -2)

Answer 1

first find the slope by subtracting the y's and putting them over the difference in x, so (7+2)/3-0) that's your slope. then put it in slope intercept form, which is y=mx+b and substitute the slope for m. then plug in one of your points and solve for b. then just move it around so it's in standard form, which means y+x+b=0

Answer 2

A good first step would be to plot the two points on a graph and draw a line through them. Then you can have an idea of the slope and where it crosses the y axis.

Standard form of an equation is:

y=ax+b

where a is the slope of the line and b is the y-intercept. You can find them mathematically by subtracting the x and y coordinates, and so forth, but graphing it gives you a "feel" for what the answer will be: that's a good way to check your work.

So first you graph it, then, find a, the slope. Like this: subtract

3 7
0 -2

3 9

So x changes by 3 in the same distance that y changes by 9. The slope of a line is y/x, so 9/3 is the slope or 3. So a=3. Now we have:

y=3x+b

To find b, you can just plug in any known x and y, and we have two: (3,7) and (0,-2) So again, you can plug in both and check your work by making sure you get the same answer both times:

7=3(3)+b
7=9+b
7-9=b
-2=b

and to check:

-2=3(0)+b
-2=0+b
-2=b

So we got the same answer both times, that's a good sign!

b= -2

So the full equation in standard form:

y=3x+(-2)
y=3x-2

Hope this helps! Stick with it, the more you practice the easier it gets, and math really is important (says the engineer :)