解方程:2x^2=3x+2;0.25X^2+2.5x-6=0;(x+2)^2=6x+7;x^2-2根号3x-6=0

3个回答

  • 2x^2=3x+2

    2x^2-3x-2=0

    (2x+1)(x-2)=0

    x=-1/2 或 x=2

    2x^2=3x+2

    x^2-3/2x-1=0

    x^2-3/2x+(3/4)^2-(3/4)^2-1=0

    (x-3/4)^2=25/16

    x-3/4=5/4或x-3/4=-5/4

    x=2或x=-1/2

    0.25X^2+2.5x-6=0;

    X^2+10x-24=0

    (x-2)(x+12)=0

    x=2 或x=-12

    0.25X^2+2.5x-6=0;

    X^2+10x-24=0

    X^2+10x+25-25-24=0

    (x+5)^2=49

    x+5=7或x+5=-7

    x=2 或x=-12

    (x+2)^2=6x+7;

    x^2+4x+4-6x-7=0

    x^2-2x-3=0

    (x-3)(x+1)=0

    x-3=0或x+1=0

    x=3 或x=-1

    (x+2)^2=6x+7;

    (x+2)^2-6(x+2)+5=0

    ((x+2)-5)((x+2)-1)=0

    (x-3)(x+1)=0

    x-3=0或x+1=0

    x=3 或x=-1

    x^2-2根号3x-6=0

    x^2-2根号3x+3-3-6=0

    (x-根号3)^2=9

    x-根号3=3或x-根号3=-3

    x=3+根号3 或x=-3+根号3

    x^2-2根号3x-6=0

    x^2-2根号3x+3-3-6=0

    (x-根号3)^2=9

    x-根号3=3或x-根号3=-3

    x=3+根号3 或x=-3+根号3

    x^2-2根号3x-6=0

    用公式法解得

    x=(2根号3+根号12+4*1*6)/2=3+根号3

    或x=(2根号3-根号12+4*1*6)/2=-3+根号3