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Question 360825: I have been trying to help my 8th grade daughter with her Algebra 1 homework. We have spent countless hours trying to figure this one out at her grade level.
The teacher is asking for an equation or rule for the following:
x values: 1, 10, 19, 28
y values: 6, 2, -2, -6
(we know that the x values increase by 9)
(we know that the y values decrease by 4)
Please help us with this, trying to figure out every combination of -4/9 ??? or something. We need a rule or equation. THANK YOU SO MUCH
Answer by ewatrrr(24785)   (Show Source):
You can put this solution on YOUR website!
Hi,
*Note: one may 'graph' the line by plotting the points and drawing the line thru them
Knowing that the x values increase by 9 as the y values decrease by 4
this discovery has led to the 'slope' of the line is (-4/9)
Note: the general slope-intecept form of an equation of a line is:
y = mx + b where m is the slope and b is the y value where the line crosses the y-axis
If you were looking for an equation of the line:
y = (-4/9)x + b
subsituting one of the ordered pairs to solve for b
(1,6)
6 = (-4/9)*1 + b
6 + 4/9) = b
58/9= b
y = (-4/9)x + 58/9 would be the equation of the line,
which could also be written in standard form by mulitplying each side of the equation by 9
4x + 9y = 58
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