Verified Answer :

(3x+4)³=2197

3x+4=z

z³=2197
z=∛2197
z=13

Then:
3x+4=13
3x=13-4
3x=9
x=9/3
x=3

answer: x=3

(3x + 4)³ = 2197

Taking the cube root in this case is easier, although we can do it the extended way which is complicated.

\(\sqrt[3]{(3x+4)^3}\) = \(\sqrt[3]{2197}\)
3x + 4 = 13

Now solve normally.

subtract 4
3x + 4 = 13
       -4    -4

3x = 9
Divide by 3 to isolate 3

\(\frac{3x}{3} = \frac{9}{3}\)
3 and 3 cancels out

x = 3