16x^4-81y^4 difference of perfect squares...
(4x^2-9y^2)(4x^2+9y^2) that's one of the equivalents...
(2x+3y)(2x-3y)(4x^2+9y^2) that's another one of them...
I think your answer is correct!
Answer:

Step-by-step explanation:
*Move terms to the left and set equal to zero:
4㏒(√x) - ㏒(3x) - ㏒(x²) = 0
*simplify each term:
㏒(x²) - ㏒(3x) - ㏒(x²)
㏒(x²÷x²) -㏒(3x)
㏒(x²÷x² / 3x)
*cancel common factor x²:
㏒(
)
*rewrite to solve for x :
10⁰ = 
1 = 
1 · x =
· x
1x = 
*that would be our answer, however, the convention is to exclude the "1" in front of variables so we are left with:
x = 
Each chore he completed he gets $3
so 5 x 3 = 15
answer is 15