I am trying to solve for the value of y when I know the x value and 2 y values.

Question

My first set of values x=23 and y=5.   The other values I know are x=43 and y=9. What are the values of y if x=18; x=33; and x=8. Please help.Im giving myself a migraine??

Answer 1

We have the following ordered pairs: (23, 5), (43, 9)

We can use these to find our line. First step is find the slope:

m = (y₂ - y₁) / (x₂ - y₁)

m = (9 - 5) / (43 - 23)

m = 4/20 → 1/5

 

Now that we know the slope, we can use the point-slope formula and convert that into the slope-intercept formula:

y - y₁ = m(x - x₁)

y - 5 = 1/5 (x - 23)

y - 5 = 1/5 x - 23/5

y = 1/5 x - 23/5 + 5

y = 1/5 x - 23/5 + 25/5

y = 1/5 x + 2/5

 

Now we can find those y values:

y = 18/5 + 2/5

y = 20/5 → 4

y = 33/5 + 2/5

y = 35/5 → 7

y = 8/5 + 2/5

y = 10/5 → 2