10X-4.9X方=0 (配方法) 和(公式法)

1个回答

  • (配方法)10X-4.9X方=0, -4.9x^2+10x=0, x^2-100/49x=0, x^2-100/49x+(50/49)^2=(50/49)^2,

    (x-50/49)^2=(50/49)^2, x-50/49=±50/49, x=±50/49+50/49

    x1=100/49, x2=0;

    (公式法)10X-4.9X方=0, -4.9x^2+10x=0,4.9x^2-10x=0,△=10^2-4*4.9*0=100

    x=(10±√100)/2*4.9=(10±10)/9.8,

    x1=(10+10)/9.8=100/49, x2=(10-10)/9.8=0