View Compilation Error

0_0_10418730_989.cpp: In function `int solve_equation(double, double, double, std::pair<double, double>&)':
0_0_10418730_989.cpp:104: error: `sqrt' undeclared (first use this function)
0_0_10418730_989.cpp:104: error: (Each undeclared identifier is reported only once for each function it appears in.)
0_0_10418730_989.cpp: In function `int main()':
0_0_10418730_989.cpp:173: error: `fabs' undeclared (first use this function)