(2x+5).(x-4)=(x-5).(4-x) 2.(9x^2+6x+1)=(3x+1)(x-2) 16x^2-8x+1=4(x+3).(4x-1)

Bởi

(2x+5).(x-4)=(x-5).(4-x)
2.(9x^2+6x+1)=(3x+1)(x-2)
16x^2-8x+1=4(x+3).(4x-1)

0 bình luận về “(2x+5).(x-4)=(x-5).(4-x) 2.(9x^2+6x+1)=(3x+1)(x-2) 16x^2-8x+1=4(x+3).(4x-1)”

  1. Đáp án:

     

    Giải thích các bước giải:

    a)(2x+5).(x-4)=(x-5).(4-x)

    ⇔(2x+5).(x-4)-(x-5).(4-x)=0

    ⇔(2x+5).(x-4)+(x-5).(x-4)=0

    ⇔(x-4)(2x+5+x-5)=0

    ⇔(x-4)3x=0

    ⇔x-4=0 hoặc 3x=0

    ⇔x=4 hoặc x=0

    b)2.(9x^2+6x+1)=(3x+1)(x-2)

    ⇔2.(3x+1)²=(3x+1)(x-2)

    ⇔2.(3x+1)²-(3x+1)(x-2)=0

    ⇔2.(3x+1)(3x+1)-(3x+1)(x-2)=0

    ⇔(6x+2)(3x+1)-(3x+1)(x-2)=0

    ⇔(3x+1)(6x+2-x+2)=0

    ⇔(3x+1)(5x+4)=0

    ⇔3x+1=0 hoặc 5x+4=0

    ⇔x= -1/3 hoặc x= -4/5

    c)16x^2-8x+1=4(x+3).(4x-1)

    ⇔(4x-1)²=4(x+3)(4x-1)

    ⇔(4x-1)(4x-1)=(4x+12)(4x-1)

    ⇔(4x-1)(4x-1)-(4x+12)(4x-1)=0

    ⇔(4x-1)(4x-1-4x-12)=0

    ⇔(4x-1).(-13)=0

    ⇔4x-1=0

    ⇔4x=1

    ⇔x=1/4

    Bình luận

Viết một bình luận