a) 1/7 + 3/7 : x = 5/14 b) (x^2 – 4)( x + 3/5) = 0 30/07/2021 Bởi Amara a) 1/7 + 3/7 : x = 5/14 b) (x^2 – 4)( x + 3/5) = 0
Đáp án + Giải thích các bước giải: a) `1/7 + 3/7 : x = 5/14``=>3/7:x=5/14-1/7``=>3/7:x=5/14-2/14``=>3/7:x=3/14``=>x=3/7:3/14``=>x=3/7*14/3``=>x=2` b) `(x^2 – 4)( x + 3/5) = 0``=>` \(\left[ \begin{array}{l}x^2-4=0\\x+\frac{3}{5}=0\end{array} \right.\) `=>` \(\left[ \begin{array}{l}x^2=0+4\\x=0-\frac{3}{5}\end{array} \right.\)`=>` \(\left[ \begin{array}{l}x^2=4\\x=\frac{-3}{5}\end{array} \right.\)`=>` \(\left[ \begin{array}{l}x=2\\x=-2\\x=\frac{-3}{5}\end{array} \right.\)Vậy `x∈{2;-2;(-3)/5}` Bình luận
Đáp án: `a,` `1/7 + 3/7 : x = 5/14` `-> 3/7 : x = 5/14 – 1/7` `-> 3/7 : x = 3/14` `-> x = 3/7 : 3/14` `-> x = 2` `text{Vậy x = 2}` `b,` `(x^2 – 4) (x + 3/5) = 0` `-> x^2 – 4 = 0` `text{hoặc}` `x + 3/5 = 0` `-> x^2 = 4` `text{hoặc}` `x = 0 – 3/5` `-> x = ±2` `text{hoặc}` `x= -3/5` `text{Vậy}` `x = 2,x=-2,x=-3/5` Bình luận
Đáp án + Giải thích các bước giải:
a)
`1/7 + 3/7 : x = 5/14`
`=>3/7:x=5/14-1/7`
`=>3/7:x=5/14-2/14`
`=>3/7:x=3/14`
`=>x=3/7:3/14`
`=>x=3/7*14/3`
`=>x=2`
b)
`(x^2 – 4)( x + 3/5) = 0`
`=>` \(\left[ \begin{array}{l}x^2-4=0\\x+\frac{3}{5}=0\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x^2=0+4\\x=0-\frac{3}{5}\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x^2=4\\x=\frac{-3}{5}\end{array} \right.\)
`=>` \(\left[ \begin{array}{l}x=2\\x=-2\\x=\frac{-3}{5}\end{array} \right.\)
Vậy `x∈{2;-2;(-3)/5}`
Đáp án:
`a,`
`1/7 + 3/7 : x = 5/14`
`-> 3/7 : x = 5/14 – 1/7`
`-> 3/7 : x = 3/14`
`-> x = 3/7 : 3/14`
`-> x = 2`
`text{Vậy x = 2}`
`b,`
`(x^2 – 4) (x + 3/5) = 0`
`-> x^2 – 4 = 0` `text{hoặc}` `x + 3/5 = 0`
`-> x^2 = 4` `text{hoặc}` `x = 0 – 3/5`
`-> x = ±2` `text{hoặc}` `x= -3/5`
`text{Vậy}` `x = 2,x=-2,x=-3/5`