OpenStudy (yato_gami):

I need help with this please! I want someone to go through the steps with me, not tell me the answer. Thanks~! ^_^ Choose the equation that represents the graph below:

9 months ago
OpenStudy (yato_gami):
9 months ago

OpenStudy (yato_gami):

A. y = −2x − 4 B. y = 2x + 4 C. y = −2x + 4 D. y = 2x − 4

9 months ago
OpenStudy (welshfella):

Hint: equations with a negative slope ( like \) have a negative coefficient of x.

9 months ago
OpenStudy (welshfella):

the general form of equation of a straight line is y = mx + b where m = slope and b = value of y where the line intersects the y-axis.

9 months ago
OpenStudy (yato_gami):

Alright, got it so far.

9 months ago
OpenStudy (yato_gami):

So the slope is going to be negative right?

9 months ago
OpenStudy (welshfella):

OK so this should lead you to the correct option check out the graphs Yes

9 months ago
OpenStudy (welshfella):

the slope = rise / run |dw:1482324219035:dw|

9 months ago
OpenStudy (3mar):

It is also an easy equation and you will be familiar with it so more.. Plotting a line using two points: - At least two points of (x,y) are sufficient to plot a straight line. - Select the easiest points from the graph through the m the line passes.

9 months ago
OpenStudy (welshfella):

yes to get value of rise / run in this case select points where the graph passes throught the axes

9 months ago
OpenStudy (3mar):

After you have picked two points, you would use this formula to form he equation of this line. You would choose the two-points formula!

9 months ago
OpenStudy (yato_gami):

So I just pick any two points on the graph?

9 months ago
OpenStudy (3mar):

yes, any two points through them the line passes. In other words, it is not logic to pick (4,4) for example!!! instead you would pick (2,-8)

9 months ago
OpenStudy (3mar):

Time for pray - 25 min

9 months ago
OpenStudy (3mar):

I think this would help you.

9 months ago
OpenStudy (3mar):

@welshfella If you don't mind, take it until I pray... Thanks in advance.

9 months ago
OpenStudy (3mar):

Sorry @Yato_Gami The electricity was off twice..

9 months ago
OpenStudy (mathmale):

Try this: Determine, just from looking at the graph, where the line crosses the y-axis. This point is called the "y-intercept" and in this case is (0,-2). Next, determine the slope of the line from inspection. yes, you could choose any two points that lie on the graph, but it'd be easiest to choose (-2,0) and (0,-4). Why? Because the line goes thru those two points exactly. From the looks of the graph, you can see immediately that the function is decreasing as x increases, so can assume immediately that the slope is negative. What is the slope? m = "rise" over run. Write the slope-intercept form of the equation of the line: y=mx+b.

9 months ago