Question 394489
I have changed the topic, since the question is not linear algebra (linear algebra studies vectors, vector spaces, and matrices).


Anyway, we have {{{x + 12/x = 7}}}. Multiplying through by x,


{{{x^2 + 12 = 7x}}}


{{{x^2 - 7x + 12 = 0}}}


This factors pretty nicely:


{{{(x-4)(x-3) = 0}}} --> x = 3, 4