Question

Answer 1

1:\(\Leftrightarrow36x^2-12x-36x^2+27x=30\)

=>15x=30

hay x=2

2: \(\Leftrightarrow4x^2-20x-7x^2+28x+3x^2=12\)

=>8x=12

hay x=3/2 

Answer 2

a, `<=> 36x^2 - 12x - 36x^2 + 27x = 30`

`=> 15x = 30`

`=> x = 2`.

b, `<=> 4x^2 - 20x - 7x^2 + 28x + 3x^2 = 12`

`=> 8x = 12`

`=> x = 3/2`.

Answer 3

`1)3x(12x-4)-9x(4x-3)=30`

`<=>36x^2-12x-36x^2+27x=30`

`<=>15x=30`

`<=>x=2`

Vậy `S={2}`

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`2)4x(x-5)-7x(x-4)+3x^2=12`

`<=>4x^2-20x-7x^2+28x+3x^2=12`

`<=>8x=12`

`<=>x=3/2`

Vậy `S={3/2}`