-2x^(2)+8x-4 in vertex form

Question

i need help turning this into vertex form

Answer 1

y = -2x² + 8x - 4

 

   = -2(x² - 8x) -4

 

   = -2(x² - 8x + 16 -16) - 4

 

   = -2(x-4)² + 32 - 4

 

y = -2(x-4)² + 28    Vertex = (4, 28)