a ) 52 * y - 24 * y = 34 6 * 32
b ) 72 * y - 14 * y = 72 * 10 - 70
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a)100-9:(372:3.y-1)-14=83
<=>100-9:(124y-1)-14=83
<=>86-9:(124y-1)=83
<=>9:(124y-1)=3
<=>124y-1=3
<=>124y=4
<=>y=\(\frac{1}{31}\approx0,3223\)
b)7260-120:24.y+924=528,3
<=>8184-5y=528,3
<=>5y=7655,7
<=>y=1531,14
c)2000-52:(615:3:y-15)-14=1984
<=>1986-52:(205:y-15)=1984
<=>52:(205:y-15)=2
<=>205:y-15=26
<=>205:y=41
<=>y=5
d)y+y.1/3+5/18=7/18
<=>4/3y=1/9
<=>y=1/12
e)13/15-(5/21+y)7/12=7/10
<=>7/12.(5/21+y)=1/6
<=>5/36+7/12y=1/6
<=>7/12y=1/36
<=>y=1/21\(\approx\)0,4762
h)y+2.y+3.y+...+10.y=49,5
<=>55y=49,5
<=>y=0,9
i)y.(1975/8.9+1885/9.10+1755/10.11+1579/11.12)=1/24
<=>7991,364899y=1/24
<=>y=33/6329161
tích nha mỏi tay quá
ĐKXĐ: \(x\ne_-^+y;y\ne0\)
Từ PT thứ 2 ta có:\(\dfrac{96}{x-y}+\dfrac{72}{x-y}=\dfrac{24}{y}\)
<=>\(\dfrac{168}{x-y}=\dfrac{24}{y}\)
<=>\(\dfrac{168}{x-y}=\dfrac{168}{7y}\)
<=>x-y=7y
<=>x=8y
Thay x=8y vào PT thứ nhất:
\(\dfrac{96}{8y+y}+\dfrac{96}{8y-y}=14\)
<=>\(\dfrac{32}{3y}+\dfrac{96}{7y}=14\)
<=>32.7y+96.3y=294y2
<=>512y=294y2
<=>y=\(\dfrac{256}{147}\left(Doy\ne0\right)\)
=>x=8y=\(\dfrac{2048}{147}\)
Vậy...
a: =25x100-150=2500-150=2350
c: \(=520:\left\{515\cdot25\right\}\)
=104/2575
Ta có
Do đó, hai đại lượng x và y không tỉ lệ thuận với nhau.
a) 5 + (-5) = 0
b) 71-52 = 19
c) 28 + (-82) = -64
d) 47 + (-30) = 17
e) (-41) + (-59) = -100
f) 75 + (-10) = 65
t) 26 - 43 = -17
y) 90 - 25 = 650
o) 72 + (-9) = 63
p) (-3) + 3 = 0
a, (-72).(15 - 49) + 15.(-56 + 72)
= -72 . 15 + 72.49 - 15.56 + 15.72
= (-72.15 + 15.72) + (72.49 - 15.56)
= 3528 - 84
= 2688
1b, 1532 + (-186) + (-1432) + (-14) + 123
= (1532 - 1432) - (186 + 14) + 123
= 100 - 200 + 123
= 223 - 200
= 23
1/ \(\left\{{}\begin{matrix}\left(x-2\right)^{72}\ge0\\\left(y+1\right)^{70}\ge0\end{matrix}\right.\)
Mà \(\left(x-2\right)^{72}+\left(y+1\right)^{70}=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(x-2\right)^{72}=0\\\left(y+1\right)^{70}=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x-2=0\\y+1=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=2\\y=-1\end{matrix}\right.\)
Vậy ...
2/ \(\left\{{}\begin{matrix}\left|x+1\right|\ge0\\\left|y-3\right|\ge0\end{matrix}\right.\)
Mà \(\left|x+1\right|+\left|y-3\right|=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left|x+1\right|=0\\\left|y-3\right|=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=-1\\y=3\end{matrix}\right.\)
Vậy ...
3/ \(\left\{{}\begin{matrix}\left(2x-10\right)^{100}\ge0\\\left(x-y\right)^{102}\ge0\end{matrix}\right.\)
Mà \(\left(2x-10\right)^{100}+\left(x-y\right)^{102}=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(2x-10\right)^{100}=0\\\left(x-y\right)^{102}=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}2x-10=0\\x-y=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=5\\y=5\end{matrix}\right.\)
Vậy ....
4/ \(\left\{{}\begin{matrix}\left|2x+8\right|\ge0\\\left|y+x\right|\ge0\end{matrix}\right.\)
Mà \(\left|2x+8\right|+\left|y+x\right|=0\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left|2x+8\right|=0\\\left|y+x\right|=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}2x+8=0\\y+x=0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}x=-8\\y=8\end{matrix}\right.\)
Vậy ..