Answer:
D: y = 2x - 2
Step-by-step explanation:
1. [tex]\frac{16-8}{9-5}[/tex] = 2
2. y = 2x + b
3. Insert the points into the equation: 8 = 10 + b
4. b = -2
5. y = 2x - 2
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Explanation:
Apply the slope formula
m = (y2-y1)/(x2-x1)
m = (16-8)/(9-5)
m = 8/4
m = 2
Then use this slope, along with another point such as (x,y) = (5,8) to find b
y = mx+b
8 = 2*5+b
8 = 10+b
8-10 = b
-2 = b
b = -2
Or you could use the other point (x,y) = (9,16)
y = mx+b
16 = 2*9+b
16 = 18+b
16-18 = b
-2 = b
b = -2
Either way, we get the same y intercept.
So because m = 2 is the slope and b = -2 is the y intercept, we go from y = mx+b to y = 2x-2
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To help verify the answer, note how plugging x = 5 leads us to...
y = 2x-2
y = 2*5 - 2
y = 10-2
y = 8
So x = 5 and y = 8 pair up together. This verifies (5,8) is on the line.
Through similar steps, you should find that the input x = 9 leads to the output y = 16. So that would confirm (9,16) is also on the line, and fully confirm the answer.
