Finding+the+Eqn+of+a+Line



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3.3-3.4- FINDING THE EQUATION OF A LINE BY HUTCH OELMAN

equations of Lines are usually given in standard form, Ax+By=C

When you find the equation of a line you can use 2 equations:

Point Slope Form- y-y1=m(x-x1)

You will be given one point on your line and a slope. If the point you are given is (4,3) you will plug that into the above equation like this:

y-3=m(x-4)

You also plug in the slope of the line for m. If the slope of the line is 2, you would insert it into the above equation like this:

y-3=2(x-4)

You then solve using algebra

y-3=2x-8 y-2x=-5

you stop here and this is your equation of the line. You can plug it into the standard form of an equation of a line to make sure your answer is right, which would look like this: -2(4)+1(3)=-5

The next equation you can use to find the equation of a line in slope-intercept form:

y=mx+b

You will use this formula if the slope and y intercept are given. The y intercept=b and the slope=m. If the y intercept of the line is 5, and the slope is -2, it would be plugged into the above formula like this:

y=-2x+5

<span style="font: normal normal normal 12px/normal Helvetica; margin: 0px;">Then use algebra to put the above formula in the standard form of an equation of a line:

<span style="font: normal normal normal 12px/normal Helvetica; margin: 0px;">y+2x=5

<span style="font: normal normal normal 12px/normal Helvetica; margin: 0px;">This is your answer. <span style="font-family: arial,helvetica,sans-serif;"> <span style="font: normal normal normal 12px/normal Helvetica; line-height: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; overflow-x: hidden; overflow-y: hidden;"> <span style="font: normal normal normal 12px/normal Helvetica; line-height: 0px; margin-bottom: 0px; margin-left: 0px; margin-right: 0px; margin-top: 0px; overflow-x: hidden; overflow-y: hidden;">