giúp mk nha;tìm x biết -3(x-1)-2(3-5x)=1 (2x+1)^2-4(x+2)^2=9 (x-1)^3-(x+3)(x^2-3x+9)+3(x^2-4)=2 16/08/2021 Bởi Adalyn giúp mk nha;tìm x biết -3(x-1)-2(3-5x)=1 (2x+1)^2-4(x+2)^2=9 (x-1)^3-(x+3)(x^2-3x+9)+3(x^2-4)=2
`-3(x-1)-2(3-5x)=1` `⇒-3x+3-6+10x=1` `⇒7x-3=1` `⇒7x=1+3=4` `⇒x=4/7` `(2x+1)^2-4(x+2)^2=9` `⇒4x^2+4x+1-4(x^2+2x+4)=9` `⇒4x^2+4x+1-4x^2-8x-16=9` `⇒-4x-15=9` `⇒-4x=9+15=24` `⇒x=24:(-4)=-6` `(x^3 – 3x^2+3x-1) – (x^3+9) +(3x^2-12) = 2` `⇒3x-22 = 2` `⇒3x =24` `⇒x= 8` Bình luận
`-3(x-1)-2(3-5x)=1`
`⇒-3x+3-6+10x=1`
`⇒7x-3=1`
`⇒7x=1+3=4`
`⇒x=4/7`
`(2x+1)^2-4(x+2)^2=9`
`⇒4x^2+4x+1-4(x^2+2x+4)=9`
`⇒4x^2+4x+1-4x^2-8x-16=9`
`⇒-4x-15=9`
`⇒-4x=9+15=24`
`⇒x=24:(-4)=-6`
`(x^3 – 3x^2+3x-1) – (x^3+9) +(3x^2-12) = 2`
`⇒3x-22 = 2`
`⇒3x =24`
`⇒x= 8`
Bạn tham khảo.