Question

3a+1/2a=5
find 4a³+1/8a³=?
Expansion​

Answer 1

Answer:

Does 1/2a equal 12a (more commonly represented with a2) , or is it meant to equal 12a ? For clarity you could have instead had a/2 or 1/(2a). There is the same issue of notation for 1/3a. What is it supposed to represent?

Here is why clarity is important. I have set the answer to equal b, but because of the ambiguity of the question, b can equal 6,63±353√18, or 5314.

3a+a2=9

⟹2(3a+a2)=9×2

⟹7a7=187

⟹a=247

2a+a3=b

⟹2(2+47)+(2+47)3=b

⟹3(5+17+(2+47)3)=3b

⟹15+2+3+47=3b

⟹3b3=183

b=6

3a+12a=9

⟹2a(3a+12a)=9×2a

⟹6a2+1=18a

⟹6a2−18a+1=0

⟹a=9±53–√6

2a+13a=b

⟹2(9±53–√6)+13(9±53–√6)=b

⟹(9±53–√6(9±53–√3)+13(9±53–√6))=(9±53–√6)×b

⟹26±153–√3+13=(9±53–√)b6

⟹6(9±53–√)=6×(9±53–√)b6

⟹b=6

Assuming a=9±53–√6

2a+a3=b

⟹2(9±53–√6)+(9±53–√6)3=b

⟹3(9±53–√3+(9±53–√6)3)=3b

⟹6((9±53–√)+9±53–√6)=18b

⟹(54±303–√)+(9±53–√)=18b

⟹18b18=63±353–√18

b=63±353–√18

Assuming a=247

2a+13a=b

⟹2(2+47)+13(2+47)=b

⟹(2+47)(5+17+13(2+47))=247×b

⟹147(13+1149+13)=147(2b+4b7)

⟹378b378=1971378

b=531