Mormon's contend their book of faith if an additional chapter in the life of Christ.
So what church do you belong to? It's a fair question. We should know what you believe is the One True Christianity™ from which the rest of us stray or have been misled by our own wicked hearts.
What church do you belong to?
If it is a Christian church that you belong to, then they state that Mormonism is not a Christian religion.
Are You Catholic? Baptist? Lutheran? Greek Orthodox, Presbyterian, Methodist, etc? Then you know that Mormonism is not a Christian religion because all Christian churches agree on that question.