Question

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

Answer 1

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?

Answer 2

i did not see dat jus it was a typo steve