tìm x biết 5x(x+1) – 3(x+1)(x-1) = 2x mũ 2 + 23 21/10/2021 Bởi Melanie tìm x biết 5x(x+1) – 3(x+1)(x-1) = 2x mũ 2 + 23
`5x(x+1)-3(x+1)(x-1)=2x^2+23` `<=>5x^2+5x-3(x^2-1)-2x^2-23=0` `<=> 5x^2+5x-3x^2+3-2x^2-23=0` `<=> 5x-20=0` `<=>5x=20` `<=>x=4` vậy pt có nghiệm x=4. Bình luận
`5x ( x + 1 ) – 3 ( x + 1 ) ( x – 1 ) = 2x² +23` `5x² + 5x – 3 ( x² – 1 ) = 2x² + 23` `3x² + 5x – 3x² + 3 = 23` `5x = 20` `x =` $\dfrac{20}{5}$ `= 4` Vậy `x = 4` Bình luận
`5x(x+1)-3(x+1)(x-1)=2x^2+23`
`<=>5x^2+5x-3(x^2-1)-2x^2-23=0`
`<=> 5x^2+5x-3x^2+3-2x^2-23=0`
`<=> 5x-20=0`
`<=>5x=20`
`<=>x=4`
vậy pt có nghiệm x=4.
`5x ( x + 1 ) – 3 ( x + 1 ) ( x – 1 ) = 2x² +23`
`5x² + 5x – 3 ( x² – 1 ) = 2x² + 23`
`3x² + 5x – 3x² + 3 = 23`
`5x = 20`
`x =` $\dfrac{20}{5}$ `= 4`
Vậy `x = 4`