View Compilation Error

0_0_14729963_26461.cpp: In function 'int main()':
0_0_14729963_26461.cpp:27:26: error: 'u12' was not declared in this scope
         double t1=(w1+w2*u12)/(v1-u2*u12);
                          ^
0_0_14729963_26461.cpp:28:29: error: expected ',' or ';' before numeric constant
         double t2=(w2-u2*t1)2;
                             ^