a, |2x -1|=15 b, 7x . ( 2+x )-7x .( x+3 )=14 c, ( x+2 ) .( x-3)=0 làm từng phép tính ra 09/11/2021 Bởi Arianna a, |2x -1|=15 b, 7x . ( 2+x )-7x .( x+3 )=14 c, ( x+2 ) .( x-3)=0 làm từng phép tính ra
`a)|2x-1|=15` `→` \(\left[ \begin{array}{l}2x-1=15\\2x-1=-15\end{array} \right.\) `→` \(\left[ \begin{array}{l}2x=15+1\\2x=-15+1\end{array} \right.\) `→` \(\left[ \begin{array}{l}2x=16\\2x=-14\end{array} \right.\) `→` \(\left[ \begin{array}{l}x=8\\x=-7\end{array} \right.\) Vậy `x∈{8;-7}` `b)7x(2+x)-7x(x+3)=14` `→7x(2+x-x-3)=14` `→7x.(-1)=14` `→7x=-14` `→x=-2` Vậy `x=-2` `c)(x+2)(x-3)=0` `→` \(\left[ \begin{array}{l}x-2=0\\x+3=0\end{array} \right.\) `→` \(\left[ \begin{array}{l}x=2\\x=-3\end{array} \right.\) Vậy `x∈{2;-3}` Bình luận
a,/2x -1/=15 ⇒2x -1=15 hoặc 2x -1=-15 2x =15+1 2x =-15+1 2x =16 2x =-14 x =16:2 x =-14:2 x =8 x =-7 Vậy :x=8 hoặc x=-7 b,7x . ( 2+x )-7x .( x+3 )=14 7x[(x+2)−(x+3)]=14 7x(x+2−x−3)=14 7x.(−1)=14 −7x=14 x=14:-7 x=−2 Vậy x = -2. c, ( x+2 ) .( x-3)=0 ⇒ (x+2)=0 hoặc ( x-3)=0 x =0-2 x =0+3 x =-2 x =3 Vậy :x=-2 hoặc x=3 Bình luận
`a)|2x-1|=15`
`→` \(\left[ \begin{array}{l}2x-1=15\\2x-1=-15\end{array} \right.\)
`→` \(\left[ \begin{array}{l}2x=15+1\\2x=-15+1\end{array} \right.\)
`→` \(\left[ \begin{array}{l}2x=16\\2x=-14\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=8\\x=-7\end{array} \right.\)
Vậy `x∈{8;-7}`
`b)7x(2+x)-7x(x+3)=14`
`→7x(2+x-x-3)=14`
`→7x.(-1)=14`
`→7x=-14`
`→x=-2`
Vậy `x=-2`
`c)(x+2)(x-3)=0`
`→` \(\left[ \begin{array}{l}x-2=0\\x+3=0\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=2\\x=-3\end{array} \right.\)
Vậy `x∈{2;-3}`
a,/2x -1/=15
⇒2x -1=15 hoặc 2x -1=-15
2x =15+1 2x =-15+1
2x =16 2x =-14
x =16:2 x =-14:2
x =8 x =-7
Vậy :x=8 hoặc x=-7
b,7x . ( 2+x )-7x .( x+3 )=14
7x[(x+2)−(x+3)]=14
7x(x+2−x−3)=14
7x.(−1)=14
−7x=14
x=14:-7
x=−2
Vậy x = -2.
c, ( x+2 ) .( x-3)=0
⇒ (x+2)=0 hoặc ( x-3)=0
x =0-2 x =0+3
x =-2 x =3
Vậy :x=-2 hoặc x=3