tìm số nguyên x biết a, 2x + 2. (-3) ²= -64 b, (-3). Ix-2I = (-3) ² – 12 20/11/2021 Bởi Adalyn tìm số nguyên x biết a, 2x + 2. (-3) ²= -64 b, (-3). Ix-2I = (-3) ² – 12
`a,2x + 2. (-3) ²= -64` `=>2x+2.9=-64` `=>2x+18=-64` `=>2x=-64-18` `=>2x=-82` `=>x=-82÷2` `=>x=-41` Vậy `x=-41` `b,(-3). |x-2| = (-3) ² – 12` `=>(-3).|x-2|=-3` `=>|x-2|=(-3)÷(-3)` `=>|x-2|=1` $⇒\left[ \begin{array}{l}x-2=1\\x-2=-1\end{array} \right.$ $⇒\left[ \begin{array}{l}x=1+2\\x=-1+2\end{array} \right.$ $⇒\left[ \begin{array}{l}x=3\\x=1\end{array} \right.$ Vậy `x=3` và `x=1` Xin hay nhất ! Bình luận
`a)2x+2(-3)^2=-64` `→2x+2.9=-64` `→2x+18=-64` `→2x=-64-18` `→2x=-82` `→x=-82:2` `→x=-41` Vậy `x=-41` `b)(-3)|x-2|=(-3)^2-12` `→(-3)|x-2|=9-12` `→(-3)|x-2|=-3` `→|x-2|=-3:-3` `→|x-2|=1` `→` \(\left[ \begin{array}{l}x-2=1\\x-2=-1\end{array} \right.\) `→` \(\left[ \begin{array}{l}x=3\\x=1\end{array} \right.\) Vậy `x∈{3;1}` Bình luận
`a,2x + 2. (-3) ²= -64`
`=>2x+2.9=-64`
`=>2x+18=-64`
`=>2x=-64-18`
`=>2x=-82`
`=>x=-82÷2`
`=>x=-41`
Vậy `x=-41`
`b,(-3). |x-2| = (-3) ² – 12`
`=>(-3).|x-2|=-3`
`=>|x-2|=(-3)÷(-3)`
`=>|x-2|=1`
$⇒\left[ \begin{array}{l}x-2=1\\x-2=-1\end{array} \right.$
$⇒\left[ \begin{array}{l}x=1+2\\x=-1+2\end{array} \right.$
$⇒\left[ \begin{array}{l}x=3\\x=1\end{array} \right.$
Vậy `x=3` và `x=1`
Xin hay nhất !
`a)2x+2(-3)^2=-64`
`→2x+2.9=-64`
`→2x+18=-64`
`→2x=-64-18`
`→2x=-82`
`→x=-82:2`
`→x=-41`
Vậy `x=-41`
`b)(-3)|x-2|=(-3)^2-12`
`→(-3)|x-2|=9-12`
`→(-3)|x-2|=-3`
`→|x-2|=-3:-3`
`→|x-2|=1`
`→` \(\left[ \begin{array}{l}x-2=1\\x-2=-1\end{array} \right.\)
`→` \(\left[ \begin{array}{l}x=3\\x=1\end{array} \right.\)
Vậy `x∈{3;1}`