C语言课程，不太弄得懂

Question

键盘输入x的值，求方程y=xx+2x-10所对应的y的值

Answer 1

#include <stdio.h>
int main()
{
    double x,y;
    scanf("%lf",&x);
    y = x*x+2*x-10;
    printf("%lf",y);
    return 0;
}