6+4x-16x²=0请用配方法算.

6+4x-16x²=0
请用配方法算.

-16x²+4x+6
=-4(4x²-x)+6
=-4(2x-1/4)²+6+1/4
-4(2x-1/4)²=-25/4
(2x-1/4)²=25/16
2x-1/4=+-5/4
x=3/4或x=-1/2