Toán 2 tìm x biết A) (2x-1/2 ) *2+(1/2+1/3+1/4):1/8=1 B) (x-3)(4-5x)=0 31/07/2021 By Alice 2 tìm x biết A) (2x-1/2 ) *2+(1/2+1/3+1/4):1/8=1 B) (x-3)(4-5x)=0
`a, (2x-1/2) .2+(1/2+1/3+1/4):1/8=1` `⇒ (2x-1/2) .2+13/12:1/8=1` `⇒ (2x-1/2) .2+26/3=1` `⇒ (2x-1/2) .2 = -23/3` `⇒ 2x – 1/2 = -23/6` `⇒ 2x = -10/3` `⇒ x = -5/3` `b, (x – 3)(4 – 5x) = 0` `⇒` \(\left[ \begin{array}{l}x – 3=0\\4 – 5x=0\end{array} \right.\) `⇒` \(\left[ \begin{array}{l}x = 3\\ 5x=4\end{array} \right.\) `⇒ x = 5` và `x = 4/5` Trả lời
Giải thích các bước giải: `A) (2x-1/2 ) *2+(1/2+1/3+1/4):1/8=1``=>(2x-1/2).2+13/12:1/8=1``=>(2x-1/2).2+13/12. 8 =1``=>(2x-1/2).2+26/3=1``=>(2x-1/2).2=-23/3``=>2x-1/2=-23/3:2``=>2x-1/2=-23/3 . 1/2``=>2x-1/2=-23/6``=>2x=-23/6+1/2``=>2x=-23/6+3/6``=>2x=-20/6``=>x=-5/3``B) (x-3)(4-5x)=0`TH`1``x-3=0=>x=0+3=>x=3`TH`2``4-5x=0=>5x=4-0=>5x=4=>x=4/5` Trả lời
`a, (2x-1/2) .2+(1/2+1/3+1/4):1/8=1`
`⇒ (2x-1/2) .2+13/12:1/8=1`
`⇒ (2x-1/2) .2+26/3=1`
`⇒ (2x-1/2) .2 = -23/3`
`⇒ 2x – 1/2 = -23/6`
`⇒ 2x = -10/3`
`⇒ x = -5/3`
`b, (x – 3)(4 – 5x) = 0`
`⇒` \(\left[ \begin{array}{l}x – 3=0\\4 – 5x=0\end{array} \right.\)
`⇒` \(\left[ \begin{array}{l}x = 3\\ 5x=4\end{array} \right.\)
`⇒ x = 5` và `x = 4/5`
Giải thích các bước giải:
`A) (2x-1/2 ) *2+(1/2+1/3+1/4):1/8=1`
`=>(2x-1/2).2+13/12:1/8=1`
`=>(2x-1/2).2+13/12. 8 =1`
`=>(2x-1/2).2+26/3=1`
`=>(2x-1/2).2=-23/3`
`=>2x-1/2=-23/3:2`
`=>2x-1/2=-23/3 . 1/2`
`=>2x-1/2=-23/6`
`=>2x=-23/6+1/2`
`=>2x=-23/6+3/6`
`=>2x=-20/6`
`=>x=-5/3`
`B) (x-3)(4-5x)=0`
TH`1`
`x-3=0=>x=0+3=>x=3`
TH`2`
`4-5x=0=>5x=4-0=>5x=4=>x=4/5`