Question 747697
We can check the correctness of a solution by testing it in the original equation. If the resulting calculation proves to be true, then our solution is correct.


{{{
(3I-20)+I=500
}}}

{{{
(3(130)-20)+(130)=500
}}}

{{{
(390-20)+(130)=500
}}}

{{{
370+130=500
}}}

which is true, so our solution is correct


:)