Given a symbolic expression how to find if starts with a minus or not=?iso-8859-1?Q?=3F_=96_mathematica.stackexchange.com?=

Given a symbolic expression how to find if starts with a minus or not? –
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I am using a Mathematica function which returns some error term in
symbolic form. I needed a way to determine if this term starts with a
minus sign or not. There will be only one term This is to ...