The ordered pairs below represent a linear relation between x and y. (-3,1),(-2,3),(-1,5),(0,7),(1,9),(2,11). Which of the following is a correct statement about this relation?
A. The slope of the line represented by this table is 2 and the y-intercept is 7.
B. The slope of the line represented by this table is 2 and the y-intercept is -4.
C. The slope of the line represented by this table is -2 and the y-intercept is -4.
D. The slope of the line represented by this table is -2 and the y-intercept is 7.

Question

The ordered pairs below represent a linear relation between x and y. (-3,1),(-2,3),(-1,5),(0,7),(1,9),(2,11). Which of the following is a correct statement about this relation?
A. The slope of the line represented by this table is 2 and the y-intercept is 7.
B. The slope of the line represented by this table is 2 and the y-intercept is -4.
C. The slope of the line represented by this table is -2 and the y-intercept is -4.
D. The slope of the line represented by this table is -2 and the y-intercept is 7.

jim_thompson5910 · Answer

what did you get

anonymous · Answer

im not too sure. since there are so many ordered pairs, how would i find one slope of the line and one y-intercept? @jim_thompson5910

jim_thompson5910 · Answer

to find the slope, pick any pair of points you want and use the slope formula

jim_thompson5910 · Answer

the y-intercept is the point of the form (0,y)

jim_thompson5910 · Answer

ie it's the point where the line crosses the y axis

anonymous · Answer

okay well i picked (1,9) and got y=1x+9. is that correct? @jim_thompson5910

jim_thompson5910 · Answer

no that's not correct

anonymous · Answer

what did i do wrong?

jim_thompson5910 · Answer

pick any two points, then use the slope formula to find the slope

anonymous · Answer

if i went with (1,9) and (2,11) would I add the two slopes of y=x+9 and y=2x+11? @jim_thompson5910

jim_thompson5910 · Answer

those are equations, not slopes

jim_thompson5910 · Answer

the slope formula is 

m = (y2 - y1)/(x2 - x1)

jim_thompson5910 · Answer

you use this formula to get a numeric value (not an equation)

anonymous · Answer

oh okay, so using points (1,9) and (2,11) I got 2/1 for the slope @jim_thompson5910

jim_thompson5910 · Answer

good, or just 2

jim_thompson5910 · Answer

so the equation looks like y = 2x + b

where b is the y-intercept

anonymous · Answer

how do i figure out the y-intercept?

jim_thompson5910 · Answer

look for the point where the x coordinate is 0

jim_thompson5910 · Answer

or...you can plug in any point in for x and y then solve for b

anonymous · Answer

if i wanted to solve it by plugging in an x and y could i pick any ordered pair or does it hae to be one of the ordered pairs ive already picked?

jim_thompson5910 · Answer

it can be any ordered pair since they all lie on the same line

anonymous · Answer

okay i used (1,9) and i got: 7=b making it y=2x+7? @jim_thompson5910

anonymous · Answer

oh, so it would be A correct? :D

jim_thompson5910 · Answer

you nailed it

anonymous · Answer

woohoo! thank you @jim_thompson5910 you're so awesome!

jim_thompson5910 · Answer

you're welcome