Tolong dibantu yaa,, aku kesusahan nihh

1a) ( 1/16)^x-2 = 64
(2-⁴)^x-2 = 2^6
----> -4 ( x - 2) = 6
----> - 4x + 8 = 6
----> - 4x = 6 - 8
----> - 4x = - 2
----> x = 2/4
----> x = ½
hp = ( ½ )

b) 2^x²+3x+4 = 4^-x-1
2^x²+3x+4 = (2²)^-x-1
----> x² + 3x + 4 = 2 ( -x - 1)
----> x² + 3x + 4 = - 2x - 2
----> x² + 3x + 2x + 4 + 2 = 0
----> x² + 5x + 6 = 0
----> ( x + 3)( x + 2) = 0
----> x = - 3 atau x = - 2
hp = ( - 3, - 2)

c) 3^x²+x-2 = 81^x+2
3^x²+x-2 = (3⁴)^x+2
----> x² + x - 2 = 4 ( x + 2)
----> x² + x - 2 = 4x + 8
---> x² + x - 4x - 2 - 8 = 0
----> x² - 3x - 10 = 0
----> ( x - 5)( x + 2) = 0
---> x = 5 atau x = - 2
hp = ( -2 , 5)