Can someone help me with this problem and show steps to your answer?

Question

1. For the line with slope -2 and passing through point (1, -2) write the equation of the line in:

a)point-slope form (1pt)
b)slope-intercept form (1pt)
c)graph the equation (2pt)

Answer 1

PART A:

The general point slope form is:
(y - y1) = m(x - x1)

Your slope (m) is -2, and your point (x1, y1) is (1, -2)
Putting it all together:
(y - (-2)) = -2(x - 1)

You probably want to simplify the -(-2) to +2:
(y + 2) = -2(x - 1)

PART B:

Continue with that equation but get y by itself and expand out the right side. You want it to end up in the form:
y = mx + b

y + 2 = -2(x - 1)
y + 2 = -2x + 2
y = -2x + (2 - 2)
y = -2x + 0
y = -2x

PART C:

This should be really easy, especialy with the point-slope form above. The y-intercept (b) is 0, so that means it goes through the point (0,0) --- the origin.

The slope is -2, which means for every change of 1 horizontally you go down 2.

Graph the following points and connect them:
(0,0)
(1, -2)
(2, -4)
(3, -6)
...

The graph should look like the attached link:

Answer 2

A) point-slope form is f(x)=m(x-x1)+y1 or
y=m(x-x1)+y1

m = the slop on the line
(x1,Y1) = a point on the line

so, in your case: m= -2 and (x1,y1) = (1,-2)

with that info just fill in the blanks to write the equation.

answer : y= -2(x-1)-2

B)Slope-intercept form is y=mx+b

m = the slope of the line
b = y-intercept (the point at which the line crosses the y-axis)
(x,y) = a point on the line

you are give m (-2) and the point on the line (1,-2). If you fill in the equation and work it out you find the answer to b, which you do not need to answer B but you will need to graph the equation in C.

now fill in the blanks to write the equation

answer: -2 = (-2)(1)+b or b= -2+2(1)

C)to graph this line you need a point on the line and the y-intercept. We learned from the slope-intercept equation that the y-intercept is -4 (which makes the point on the graph (0,-4)

so, on graph paper, draw a dot on your point (1,-2) and a dot on (0,-4) then draw a line with a straight edge through each points

Answer 3

1. point slope form is y2 = m(x2 - x1) +y1

You know x2 and y2 (1,-2) and you know the slope so just plug in 0 for x1 (there will be a y intercept where x will equal zero) and solve for y1

2. slope intercept form is y2 = m(x1) + y1

This is a lot like the above one and can be worked out the same.

3. Can't graph stuff here for you but know that you know two points from doing the above work, you should be able to plot them, draw the line through them, and look there, you got a graph.

Answer 4

a.) y-y(1)=m (x-x1)

b.) y=mx+b

ex.)
The equation of a line with slope -2 and the point (4,6)


y - 6 = -2( x - 4)
y - 6 = -2x + 8
2x + y = 14

to learn how to work your own problem, I would suggest http://mathforum.org/library/drmath/view/54520.html

Its where I learned to work difficult problems in college algebra and survey of math. Also, you can write him with your own problems. Good Luck!!!

Answer 5

y = mx+b

x=1 y=-2 m-2

-2= -2*1 +b

b=0

equation is

y=-2x

i suppose