Answer:
C
Step-by-step explanation:
We want a line of best fit, which means we want to create a line that the data points will lie closest to.
One thing we can do is find the slope between the bottom-leftmost point and the top-rightmost point. This is because if we were to draw a line connecting these two, it will cut through the data quite well.
Those two points are (9, 15) and (16, 18), so the slope is change in y divided by the change in x:
(18 - 15) ÷ (16 - 9) = 3 ÷ 7 ≈ 0.4
Eliminate A and B.
Now we need to determine the y-intercept. This needs no calculations; simply look at the graph: there's no way a line cutting through the y-intercept point of (0, 18) will perfectly match the data points; instead it must be a y-intercept lower than 18. So, eliminate D.
The answer is C.
For perpendicular lines, the slopes are negative reciprocals of one another. Therefore, the slope of QC = 3/2
Using this into the formula of slope:
3/2 = (y + 6) / (-1 + 3)
y = -9
If the slope of CD is 2/3, then y works out to be -3.
To solve, isolate the x. Cross multiply
3/13(13)(5) = x/5(5)(13)
3(5) = (13)x
Simplify
13x = 15
Isolate the x. Divide by 13.
13x/13 = 15/13
x = 15/13
x = 1.2
1.2 is your answer
hope this helps
-2/3x+9=4/3x-3 original problem add 2/3x to both sides
9=6/3x-3 simplify 6/3 to 2 and add 3 to both sides
12=2x divide both sides by 2
x=6
hope that helps
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