## 3psilon 3 years ago Why is 3^20 + 3^20 + 3^20 == 3^21 ??!? I'm so confused

1. TuringTest

3^20+3^20+3^20 combine like terms... =3(3^20)=3^(20+1)=3^21

2. anonymous

|dw:1344353759006:dw|

3. TuringTest

@3psilon let me know if you still don't get it...

4. 3psilon

So you're factoring out the 3?

5. 3psilon

Not sure how you go tto 3^(20+1)

6. TuringTest

no, I am combining like terms call$(3^{20})=x$we then have$(3^{20})+(3^{20})+(3^{20})=x+x+x=3x$sub back in what we know x is...$3x=3(3^{20})$now we use the property$x^a\cdot x^b=x^{a+b}$and get$3(3^{20})=3^1\cdot3^{20}=3^{20+1}=3^{21}$

7. 3psilon

OHHHH

8. 3psilon

Yes! I thought I got it last night, but then I saw this problem and was embarrassed to ask again. Thank you turing

9. TuringTest