Respuesta :

hello :
f(x) =7x²+42x
f(x) = 7(x²+6x)
f(x) = 7 (x²+2(3)(x)+3²-3²)
f(x) = 7 ((x+3)² -9)
f(x) =7(x+3)² -63....( vertex form)

D on edg 2021 :)

i hope i could help