Question

Tìm x biết :2x+3/5x+2 = 4x+5/10x+2

Answer 1

2x+3/5x+2 = 4x+5/10x+2

<=> (2x+3)(10x+2)=(5x+2)(4x+5)

<=>2x(10x+2)+3(10x+2)= 5x(4x+5)+2(4x+5)

<=> 20x^2+4x+20x+6 = 20x^2+25x+9x+10

<=> 20x^2+4x+20x+6 - (20x^2+25x+9x+10)=0 => 20x^2+24x+6-(20x^2+34x+10)=0

                                                                  <=>   -10x-4=0

                                                                 <=>-10x=4

                                                                  <=> x= -4/10

Answer 2

2x+3/5x+2=4x+5/10x+2

=> (2x+3)(10x+2)=(5x+2)(4x+5)

=> 20x^2+4x+30x+6=10x^2+25x+8x+10 ( Vì cả hai vế đều có 10x^2 nên ta xóa đi )

=> 34x+6=33x+10

=> 34x-33x=-6+10

=> x=4

 

Answer 3

x⁴+5x²-9x +3

Tìm x?

Answer 4

2x+3/5x+2=4x+5/10x+2

<=>(2x+3)(10x+2)=(4x+5).(5x+2)

<=>2x.(10x+2)+3.(10x+2)=5x.(4x+5)+2.(4x+5)

<=>20x^2+4x+30x+6=20x^2+25x+8x+10

<=>4x+30x+6=20x^2+25x+8x+10-20x^2

<=>x.(4+30)+6=(20x^2-20x^2)+x.(25+8)+10

<=>34x+6=0+33x+10

<=>34x-33x=10-6

<=>x=4

Vậy x=4