Đáp án+Giải thích các bước giải:
`a) (2x+3)(x-4)+(x-5)(x-2)=(3x-5)(x-4)`
`⇔(2x+3)(x-4)+(x-5)(x-2)-(3x-5)(x-4)=0`
`⇔2x²-8x+3x-12+x²-2x-5x+10-(3x²-12x-5x+20)=0`
`⇔2x²-8x+3x-12+x²-2x-5x+10-3x²+12x+5x-20=0`
`⇔5x−22=0`
`⇔5x=22`
`⇔x=22/5`
Vậy `S={22/5}`
`b) 2x²+3(x-1)(x+1)=5x(x+1)`
`⇔2x²+3(x²+x-x-1)=5x²+5x`
`⇔2x²+3x²+3x-3x-3=5x²+5x`
`⇔2x²+3x²+3x-3x-3-(5x²+5x)=0`
`⇔2x²+3x²+3x-3x-3-5x²-5x=0`
`⇔−5x−3=0`
`⇔-5x=3`
`⇔x=-3/5`
Vậy `S={-3/5}`
Chúc bn hc tốt🥰
$\text{#LinhSad}$
