реши уравнение 9(143-13х)=234

http://tex.z-dn.net/?f=9%28143-13x%29%3D234+%5C%5C+1287-117x%3D234+%5C%5C+-117x%3D-1053+%5C%5C+x%3D-1053%2F%28-117%29+%5C%5C++x%3D9

(9*143)-(9*13х)=2341287-117х=234-117х=-1053х=1053/117х=9