I'm not that good at explaining but here are my answers:
1- 170
2-340
3- 9 months for $140 and 14 months for $190
4- 10
5-If the x (or months savings) goes up or down, so does the y (or account balance)
6- 70y +20n= 2x
explanation:
1- 150 + 20 = 170
2- 170*2= 340
3-the number always goes up by 20, if it's something like an uneven number, let's say 3, which is after 2, add 10.
4- can't explain this, I used a calculator
5- i don't think I have to explain
6- I don't know, I just took a random equation and "plugged in" the numbers from the equation I was working on.