Question 547018
{{{7+x=2x}}}
Subtract x from both sides of the equation
{{{7+x-x=2x-x}}}
{{{7+cross(x)-cross(x)=x}}}
{{{7=x}}}
{{{x=7}}}

Check
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Put the value of x in the equation
{{{7+x=2x}}}
{{{7+7=2(7)}}}
{{{14=14}}}