Ageometric series has 3 terms. the sum of the three terms is 42. the third term is 3.2 times the sum of the other two terms. what are the three terms?

Ok so the series is x,y,and z
x+y+z=42
3.2(x+y)=z

rearrange the first equation to get
z=42-x-y

3.2(x+y)=42-x-y
OR
3.2x+3.2y=42-x-y

combine the x's and y's to one side

4.2x+4.2y=42

divide everything by 4.2

x+y=10

place that into the first equation

10+z=42

subtract 10 from both sides

z=32

the other 2 terms have to be smaller by a constant multiple knowing the number 32 divides nicely by 8 and 4 we can try both of those number i started with 8 so 8times4 gives you 32 and if you divide 8 by 4 you get 2 8=y and x=2 x+y=10 those work!! hope this helps