Question 92739
{{{2+a=2a}}} Set the expressions equal to each other


{{{2+cross(a-a)=2a-a}}} Subtract "a" from both sides



{{{2=a}}} Combine like terms


So the number is


{{{a=2}}}


Check:


{{{2+2=4}}} plug in {{{a=2}}} into {{{2+a}}}


{{{2(2)=4}}} plug in {{{a=2}}} into {{{2a}}}


Since they both equal 4, the solution works