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Ta có:
135 , 2 − y = 52 , 53 + 16 , 7 135 , 2 − y = 69 , 23 y = 135 , 2 − 69 , 23 y = 65 , 97
Vậy y = 65,97
Đáp án A
| a) 40,43 – x = 2,8 | b) 81,65 – x = 20 |
| x = 40,43 – 2,8 | x = 81,65 – 20 |
| x = 37,63. | x = 61,65. |
| Vậy x = 37,63. | Vậy x = 61,65. |
\(a,\Leftrightarrow y^{200}-y=y\left(y^{199}-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}y=0\\y^{199}=1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}y=0\\y=1\end{matrix}\right.\)
Vậy ..
\(b,\Leftrightarrow y^{2010}-y^{2008}=y^{2008}\left(y^2-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}y^{2008}=0\\y^2=1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}y=0\\y=1\\y=-1\end{matrix}\right.\)
Vậy ...
\(c,\Leftrightarrow\left(2y-1\right)^{50}-\left(2y-1\right)=\left(2y-1\right)\left(\left(2y-1\right)^{49}-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}2y-1=0\\\left(2y-1\right)^{49}=1\end{matrix}\right.\)
\(\Leftrightarrow y=\dfrac{1}{2}\)
Vậy ..
\(d,\Leftrightarrow\left(\dfrac{y}{3}-5\right)^{2008}\left(\left(\dfrac{y}{3}-5\right)^2-1\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}\left(\dfrac{y}{3}-5\right)^{2008}=0\\\left(\dfrac{y}{3}-5\right)^2=1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{y}{3}-5=0\\\dfrac{y}{3}-5=1\\\dfrac{y}{3}-5=-1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}y=15\\y=18\\y=12\end{matrix}\right.\)
Vậy ..
a)\(25,5+y-12,5=4.7\)
⇔\(13+y=28\)
⇔\(y=15\)
b)\(76,22-y-25,7=30+5,52\)
⇔\(50,52-y=35,52\)
⇔\(y=15\)
c)\(4,5-y+1,2=3,5\)
⇔\(5,7-y=3,5\)
⇔\(y=2,2\)
\(a,\Rightarrow10+y=28\\ \Rightarrow y=18\\ b,\Rightarrow50,52-y=35,52\\ \Rightarrow y=15\\ c,\Rightarrow5,7-y=3,5\\ \Rightarrow y=2,2\)
Lời giải:
$y\times 3,5=22,19$
$y=22,19:3,5=6,34$
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$48,3-y\times 2,8=30,716$
$y\times 2,8=48,3-30,716=17,584$
$y=17,584:2,8=6,28$
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$y:5,7-5,6=12,5$
$y:5,7=12,5+5,6=18,1$
$y=18,1\times 5,7=103,17$
`a, y xx 2,8 + 47,8 = 61,24`
`=> y xx 2,8=61,24 - 47,8`
`=> y xx 2,8=13,44`
`=> y=13,44 : 2,8`
`=>y=4,8`
`b, 13,9 + y : 5,7 = 26,23`
`=> y : 5,7 = 26,23-13,9`
`=> y : 5,7 =12,33`
`=> y= 12,33 xx 5,7`
`=>y= 70,281`
`c, 68,5 - y xx 2,8 = 49,18`
`=> y xx 2,8 = 68,5 - 49,18`
`=> y xx 2,8 =19,32`
`=>y=19,32 : 2,8`
`=>y=6,9`
`d, y : 5,7 - 3,6 = 5,8`
`=> y : 5,7 = 5,8 + 3,6`
`=> y : 5,7=9,4`
`=>y=9,4 xx 5,7`
`=>y= 53,58`
a) \(\left|2x\right|-\left|-2,5\right|=\left|-7,5\right|\)
\(\Leftrightarrow\left|2x\right|-2,5=7,5\)
\(\Leftrightarrow\left|2x\right|=10\)
\(\Leftrightarrow\begin{cases}x\ge0\\2x=10\end{cases}\) hoặc \(\begin{cases}x< 0\\2x=-10\end{cases}\)
\(\Leftrightarrow\begin{cases}x\ge0\\x=5\left(tm\right)\end{cases}\) hoặc \(\begin{cases}x< 0\\x=-5\left(tm\right)\end{cases}\)
Vậy x={5;-5}
b)\(\left|3x\right|\cdot\left|-3,5\right|=\left|-2,8\right|\)
\(\Leftrightarrow\left|3x\right|\cdot3,5=2,8\)
\(\Leftrightarrow\left|3x\right|=\frac{4}{5}\)
\(\Leftrightarrow\begin{cases}x\ge0\\3x=\frac{4}{5}\end{cases}\) hoặc \(\begin{cases}x< 0\\3x=-\frac{4}{5}\end{cases}\)
\(\Leftrightarrow\begin{cases}x\ge0\\x=\frac{4}{15}\end{cases}\) hoặc \(\begin{cases}x< 0\\x=-\frac{4}{15}\end{cases}\)
Vậy x={4/15;-4/15}
c) \(\left(3x-5\right)\left(\frac{3}{2}x+2\right)\left(0,5x-10\right)=0\)
\(\Leftrightarrow\left[\begin{array}{nghiempt}3x-5=0\\\frac{3}{2}x+2=0\\0,5x-10=0\end{array}\right.\)\(\Leftrightarrow\left[\begin{array}{nghiempt}x=\frac{5}{3}\\x=-\frac{4}{3}\\x=20\end{array}\right.\)
a)|2x|-|-2,5|=|-7,5|
|2x|-2,5=7,5
|2x|=10
\(\Rightarrow\left[\begin{array}{nghiempt}2x=10\\2x=-10\end{array}\right.\)\(\Rightarrow\left[\begin{array}{nghiempt}x=5\\x=-5\end{array}\right.\)
Vậy x=5;-5
Lớp 3 chưa học cộng trừ như 40,43 - y = 2,8 đâu bạn
bài lớp 5 mà