Question

If 3^2x^2-9x = 81^-1 ,then x equals to

Answer 1

3^2x^2 - 9x = 81 ^-1

3^2x^2-9x = 3^-4

When bases are same exponents are equal

 So 2x^2-9x = -4

2x^2 - 9x + 4 = 0

2x^2-8x-x+4 = 0

2x(x - 4) - 1(x - 4) = 0

x - 4 = 0 and 2x - 1= 0

x = 4 and x = 1/2