How do you write the equation #y=x^2+18x+90# in vertex form?

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Answer 1 · 2018-03-17T04:32:16

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#y=(x+9)^2+9#
# #

# #
By using the completing square method, you can accomplish that.

#y=x^2+2(x)(9)+9^2+90-9^2#

#y=(x+9)^2+90-81#

#y=(x+9)^2+9#

Which is the required vertex form with the vertex at #\ \ (-9,9)\ #.

# #

That's it!