Question

Predict the y-value if x = -3.

x: -1, 0, 1, 2.
y: 5, 3, 1, -1.

I thought was the x value was: -1, 0, 1, 2? Not x=-3.... how can this be?


?????? Please help :(

Answer 1

you have a constant difference between y values, can you spot that difference?

Answer 2

the difference in x's pattern is adding 1 from -1.
in y's pattern it's by adding -2 from 5.

is that what you were asking?

Answer 3

yes, thats what I was asking;

since y changes by -2 when x changes by +1 we can create a slope by stacking y/x

slope = -2/1, or simply -2

notice that when x=0 we have a y value, known as the y intercept value; do you see it?

Answer 4

this method is a bit overkill for this problem, but its a good idea to have

Answer 5

I think I understand it better :)

Answer 6

using a slope intercept from of a line: y = mx+b we can construct a model to predict the unknown value

y = -2x +3

Answer 7

otherwise, we could have simply went backwards from 5 to get 2 extra spots


-3 -2 -1
9 7 5
+2 +2

Answer 8

Okay thank you so much :) !!