Double Sided Formula

I'm not rescuing people, I'm solving equations. He is not killing people, he is solving another way of writing the same problem. A formula with two sides. On the one hand, we protect the "company" and save people's lives on the verge of collapse. Hit "brittle" on one side to accurately break down the weakest points of things. In an accident seven years ago, Shen Yan used a push to rescue the girl next door in the rubble, but he missed a variable and watched her stop jumping twice. The guilt of "I haven't finished all the calculations" became the only obsession that he dared not let go in the next six years: only save but not kill, and always push the situation to the end. Until one day, a call from an unknown address came to his mobile phone: "You did a good job with the steel cable yesterday. But your hands are a little shaky. Next time I will choose a place with a lot of people." The other party uses the same strings and the same parameter system as him. It's just that the direction is opposite - he uses the Sheng style to protect the "continuous", and the opponent uses the destroying style to hit the "Break". They solved the same paper. One answer area said "protect" and the other answer area said "destroy". The two incomplete formulas in their hands were originally a complete formula - they were split into two halves and passed to two people. This is not a showdown between good and evil, but a question divided into two halves, waiting for one person to write down two answers at the same time.