Tuesday

April 28, 2015

April 28, 2015

Posted by **Gabby** on Saturday, November 23, 2013 at 2:28pm.

Part 2: Choose 1 set of points from the choices below. Then, solve the problem and post your solution, showing your steps.

Write an equation in point-slope form for the line that passes through one of the following pairs of points (you may choose the pair you want to work with). Then, use the same set of points to write the equation in standard form and again in slope-intercept form.

Point pairs

(5, 1), (–3, 4)

(0, –2), (3, 2)

(–2, –1), (1, 2)

Part 3: View and comment on the work of at least 2 other students. If possible, choose students' whose work is based on different sets of points from the ones you chose.

I need help from Steve and or Reiny, I've done work similar to this but not this.....

- Math-Algebra 1 -
**Reiny**, Saturday, November 23, 2013 at 3:02pmDifferent texts use slightly different names for the form of the linear equation.

e.g

4x + 3y -12 = 0 -----> I would call general form

4x + 3y = 12 -------> standard form

y = (-4/3)x + 4 ---- > slope-y intercept form

point-slope form is a starting equation, usually ending up with one of the above.

Which ever method you use, finding the slope is a good start.

I will do the first one:

2 points (5,1) and (-3,4)

slope = (4-1)/(-3-5) = 3/-8 or -3/8

using (5,1)

y-1 = (-3/8)(x-5) from y - y1 = m(x - x1)

at this point multiply each side by the denominator of the slope, if the slope is a fraction

8y - 8 = -3(x-5)

your fractions have disappeared, yeahhh!

8y - 8 = -3x + 15

3x + 8y = 23

at this stage I use the point that was not used and test if it satisfies my equation.

for (-3,4)

LS = 3(-3) + 8(4) = -9+32 = 23

RS = 23 , all is good!

Once you have the equation is the simple form of

3x + 8y = 23, you can go to any of the others

changing it to slope - y intercept form takes 2 steps

1. keep only the y term on the left side

3x + 8y = 23 -------> 8y = -3x + 23

2. divide each term by the coeffiecient of the y term

------> y = (-3/8)x) + 23/8

try the other two, let me know what you get

- Math-Algebra 1 -
**Gabby**, Saturday, November 23, 2013 at 3:23pmPart 2:

The point pairs chosen is (5, 1) and (-3, 4). First of all, the slope must be found out.

The formula for it is: slope = rise/run

slope = (4 - 1)/(-3 -5) = 3/-8 = -3/8

Point slope form: y - 1 = -3 (x - 5)/8

Slope intercept form: y - 1 = -3x/8 + 15/8

y = -3x/8 + 23/8

Standard form: 8y = -3x + 23

- Math-Algebra 1 -
**Gabby**, Saturday, November 23, 2013 at 3:23pmThats all I rlly needed, thx~!