Question

Answer 1

a) 8x(x-5) -2x(4x+3)=92

<=> 8x²-40x-8x²-6x=92

<=>-46x=92

<=>x=-2

Vậy S={-2}

 

b)9x(x+4)-3x(3x+2)=120

<=> 9x²+36x-9x²-6x=120

<=>30x=120

<=> x=4

Vậy S={4}

   

C) 12x(1-x)+4x(3x+7)=-240

<=>12x-12x²+12x²+28x=-240

<=>40x=-240

<=>x=-4

Vậy S={-4}

Answer 2

a. 8x(x-5)-2x(4x+3)=92
<=>8x²-40x-8x²-6x=92
<=>-46x=92
<=>x=-2
Vậy x = -2

b. 9x(x+4)-3x(3x+2)=120
<=>9x²+36x-9x²-6x=120
<=>30x=120
<=>x=4
Vậy x = 4

c. 12x(1-x)+4x(3x+7)=-240
<=>12x-12x²+12x²+48x=-240
<=>60x=-240
<=>x = -4
Vậy x = -4