‘2’是平方 1. -2ac2/14a2bc 2. 4-a2/a2-2a 3. x2-16/2x+8 4.x2-16/8

1个回答

  • (1)

    (-2ac2)/(14a2bc)

    =-c/7ab

    =-c/7ab

    (2)

    (4-a2)/(a2-2a)

    =(22-a2)/a(a-2)

    =(2+a)(2-a)/-a(2-a)

    =2+a/-a

    =-2+a/a

    (3)

    (x2-16)/2x+8

    =(x2-42)/2(x+4)

    =(x+4)(x-4)/2(x+4)

    =x-4/2

    4.

    (x2-16)/8-2x,其中x=-2

    (x2-16)/8-2x

    =(x2-42)/2(4-x)

    =(x+4)(x-4)/-2(x-4)

    =x+4/-2

    =-x+4/2

    =--2+4/2

    =-2/2

    =-1