Đáp án+Giải thích các bước giải:
`a) (3x-5)(5-3x)+9(x+1)²=30`
`⇔15x-9x²-25+15x+9(x²+2x+1)=30`
`⇔15x-9x²-25+15x+9x²+18x+9=30`
`⇔48x-16=30`
`⇔48x=46`
`⇔x=23/24`
Vậy `x=23/24`
`b) (x+4)²-(x+1)(x-1)=16`
`⇔x²+8x+16-(x²-x+x-1)=16`
`⇔x²+8x+16-x²+x-x+1=16`
`⇔8x+17=16`
`⇔8x=-1`
`⇔x=-1/8`
Vậy `x=-1/8`
Chúc bn hc tốt🥰
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