Question 1012686: Write the equation of the arithmetic sequence.
5, 10, 15, 20, ....
y= ______________________
My 6th grade son is doing prealgebra and I am confused on what they are trying to do here.
Found 4 solutions by algebra hello, Fombitz, addingup, ikleyn:
Answer by algebra hello(55)   (Show Source):
You can put this solution on YOUR website! In arithmatic progression common difference d is constant.In the given series
d=second term-first term
=10-5
=5
so the series is
5,10,15,20,25,30,35,40,45,50,55,................
Answer by Fombitz(32388)  (Show Source):
Answer by addingup(3677)  (Show Source):
You can put this solution on YOUR website! You got some good answers. But I looked at the problem and see that you have a y=_______ which tells me that the teacher is looking for an expression in the form of the slope-intercept formula y= mx+b, which by the way, is used in sequences such as the problem you posted but not frequently.
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We have:
Position x: 1--2--3--4
Units.......5-10-15-20 (note: dashes are spaces, not minus signs)
So we find our answer in the change in units divided by the change in position. Change is represented by the Greek letter delta:
Δunits/Δposition
Take any one, let's take 15 units in position 3:
15/3=5 So now we can express an equation in slope-intercept form:
#units y = 5x+b Now solve for b. Pick any position and its corresponding units, I'll use position 2 (10 units):
10 = 5(2)+b Multiply
10= 10+b subtract 10 on both sides
0= b In this particular exercise, b= 0. And it can be checked:
y= mx+b
20=5(4)+0 and 5*4+0= 20, so we have a good equation 20=20
This is not for the weak of heart, good luck ;-)
Answer by ikleyn(52781)  (Show Source):
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