Question

tìm x

` ((-3)^x .3^6)/(-27.9^x) =-3`

Answer 1

\(\dfrac{\left(-3\right)^x.3^6}{-\left(3\right)^3.9^x}=-3\)

\(=>\dfrac{\left(-3\right)^x.3^6}{9^x.-\left(3\right)^3}=-3\)

`=>`\(\dfrac{\left(-3\right)^x}{9^x}.\dfrac{3^6}{-\left(3\right)^3}=-3\)

`=>`\(\left(-\dfrac{3}{9}\right)^x.\left(-3\right)^3=-3\)

`=>`\(\left(-\dfrac{1}{3}\right)^x=\dfrac{1}{9}\)

`=>`\(\left(-\dfrac{1}{3}\right)^x=\left(-\dfrac{1}{3}\right)^2\)

`=> x = 2`

Vậy `x = 2`

Answer 2

\(\dfrac{\left(-3\right)^x\cdot3^6}{-27\cdot9^x}=-3\)

=>\(\dfrac{\left(-3\right)^x}{9^x}\cdot\dfrac{3^6}{-3^3}=-3\)

=>\(\left(-\dfrac{3}{9}\right)^x\cdot\left(-3\right)^3=-3\)

=>\(\left(-\dfrac{1}{3}\right)^x=\dfrac{\left(-3\right)}{\left(-3\right)^3}=\dfrac{-3}{-27}=\dfrac{1}{9}\)

=>x=2