9^x(-2)+3^3x=81.... here is wat i did bt i go confuse
(3^x)(-4)+(3^x)3=81 let 3^x=b
b/4+b^3=81 multiply tru 4
b+b^3=81
Not sure what your parentheses mean. Multiplication, or more powers
9^x(-2) means -2*9^x or (9^x)^-2 = 9^(-2x)
Why do you sometimes use ^ for powers, and other times not?
i did not see dat jus it was a typo steve
To solve the equation 9^x(-2) + 3^(3x) = 81, you followed the correct steps so far by substituting 3^x = b. Here's how you can proceed from there:
1. Rewrite the original equation using the substitution b for 3^x:
b/4 + b^3 = 81
2. Multiply through by 4 to eliminate the fraction:
4(b/4) + 4(b^3) = 4(81)
b + 4b^3 = 324
3. Rearrange the equation:
4b^3 + b = 324
Now, the equation is a cubic equation in terms of b. To solve it, you can try to factor it or use numerical methods like Newton's method to approximate the solution.
If you wish to proceed further and find the value of x, you will need to substitute back the value of b into the equation: 3^x = b.