初二上半学期数学一元二次方程(用因式分解法,

4个回答

  • 1.x-√3=-4x(x-√3)

    (x-√3)(1+4x)=0

    x=√3或-1/4

    2.(2x+√3)(5x+√7)=0

    x=-√3/2或-√7/5

    3.[3(x-2)+4(x+1)][3(x-2)-4(x+1)]=0

    -(7x-2)(x+10)=0

    x=2/7或-10

    4.[(2x+1)+1][(2x+1)+2]=0

    2(x+1)(2x+3)=0

    x=-1或-3/2

    5.(x+√3)[x+(1+√3)]=0

    x=-√3或-(1+√3)

    7.[(x-3)+(x-5)][(x-3)-(x-5)]+(x+4)²-17x-24=0

    2 (2x-8)+(x+4)²-17x-24=0

    (x+4)²-13x-40=0

    x²-5x-24=0

    (x+3)(x-8)=0

    x=-3或8

    8.(x+a)[x+(a+1)]=0

    x=-a或-(a+1)

    9.15x²-5√2x-3√3x+√6=0

    (3x-√2)(5x-√3)=0

    x=√2/3或√3/5

    10.(x-√2)[(1+√2)x-1]=0

    x=√2或1/(1+√2)

    11.x²-3x-4=0 (x>0) 或 x²+3x-4=0 (x0)或 (x+4)(x-1)=0 (x