Respuesta :

calculista
we know that
the vertex form of the equation is
y=a(x-h)²+k

we have 
y = 7x² + 14x +4
y=7(x² + 2x) +4
y=7(x² + 2x+1-1) +4
y=7(x² + 2x+1) +4-7
y=7(x+1)²-3

the answer is
y=7(x+1)²-3