using namespace std; int main() double x,y; cin >>x; if(x<5&&×>=0) f y=-x+2.5; } if(x>=5&&×<10) { y=2-1.5*(x-3)*(x-3); } if(x>=10&&x<20) { y=x/2-1.5; } cout <fixed <<setprecision(3)<<y <<endl; return 0;using namespace std; int main() { double x,y; cin >>x; if( x < 5 && x >= 0) { y = -x + 2.5; } if(x >= 5 && x < 10) { y = 2-1.5*(x-3)*(x-3); } if( x >= 10 &&x < 20) { y = x/2 -1.5; } cout << fixed <<setprecision(3) <<y <<endl; return 0; }