x+13=53 tim x
:D
tim x :x-20/11*13-20/13*15-...20/53*55=3/11
Tim X
a,X - 20/11 x 13 - 20/13 x 15 - 20/15 x 17 -...-20/53 x 55 = 3/11
b,1/21 + 1/28 +1/36 + ... +2/Xx(x + 1) = 2/9
Ta có : A=20/11×13 + 20/13×15 +20/15×17+...+20/53×55
A = 10 ×( 2/11×13+2/13×15+...12/53×55)
A = 10 ×(1/11-1/13+1/13-1/15+1/15-1/17+...+1/53-1/55)
A = 10 × (1/11-1/55)
A =10 × 4/55
A = 8/11
Bài 1: Tìm x:
d) \(\left|2x+1\right|=\left|x-1\right|\)
f) \(\left|x-1\right|-1=50-2.\left|x-1\right|\)
d, \(\left|2x+1\right|=\left|x-1\right|\)
TH1 : 2x + 1 = x - 1 <=> x = -2
TH2 : 2x + 1 = 1 - x <=> 3x = 0 <=> x = 0
f, | x - 1 | - 1 = 50 - 2 | x - 1 |
<=> 3 | x - 1 | = 51 <=> | x - 1 | = 17
TH1 : x - 1 = 17 <=> x = 18
TH2 : x - 1 = -17 <=> x = -16
d) Ta có: \(\left|2x+1\right|=\left|x-1\right|\)
\(\Leftrightarrow\left[{}\begin{matrix}2x+1=x-1\\2x+1=1-x\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}2x-x=-1-1\\2x+x=1-1\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-2\\x=0\end{matrix}\right.\)
f) Ta có: \(\left|x-1\right|-1=50-2\left|x-1\right|\)
\(\Leftrightarrow3\left|x-1\right|=51\)
\(\Leftrightarrow\left|x-1\right|=17\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=17\\x-1=-17\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=18\\x=-16\end{matrix}\right.\)
341*67+341*16+659*83
( 44*53*60):(11*13+15)
TIM X
(X+74)-318=200
2636:(12*X-91)=36(X:23+45)*67=8911
\(341.67+341.16+659.83=341\left(67+16\right)+659.83\)
\(=341.83+659.83\)
\(=83\left(341+659\right)\)
\(=83.1000=83000\)
341x67+341x16+659x83
=341x(67+16)+659x83
=341x83+659x83
=83x(341+659)
=83x1000
=83000
nhớ tk mk nhé các bn
tim ƯCLN CỦA 13 VÀ 53
5 NGUOI LAM NHANH NHAT SE DUOC TIC
Vì 13 và 53 là hai số nguyên tố cùng nhau nên ƯCLN(13,53)=13.53=689
Tìm x:
d) \(\dfrac{-5}{6}-x=\dfrac{7}{12}+\dfrac{-1}{3}\)
e) \(\dfrac{x+3}{-15}=\dfrac{1}{3}\)
f) \(\left(4,5-2x\right).\left(-1\dfrac{4}{7}\right)=\dfrac{11}{14}\)
d: =>-x-5/6=7/12-4/12=3/12=1/4
=>-x=1/4+5/6=13/12
hay x=-13/12
e: =>x+3=-5
hay x=-8
f: =>4,5-2x=-1/2
=>2x=5
hay x=5/2
tìm x:d) x852y chia hết 5,chia 3 dư 1
Tim X :
x : 2 + 17 = 53
Tìm m để các bất phương trình sau đây có nghiệm đúng với mọi x:
d) mx2 + (m-1)x + m - 1 < 0
e) (m - 1)x2 - 2(m+1)x + 3(m-2) > 0
f) | 3(m + 6)x2 - 3(m + 3)x + 2m - 3 | > 3
d: \(\Delta=m^2-2m+1-4m\left(m-1\right)=m^2-2m+1-4m^2+4m=-3m^2+2m+1\)
Để bất phương trình có nghiệm đúng với mọi x thì \(\left\{{}\begin{matrix}-3m^2+3m-m+1< 0\\m< 0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\left(m-1\right)\left(-3m+1\right)< 0\\m< 0\end{matrix}\right.\)
\(\Leftrightarrow\left\{{}\begin{matrix}\left(m-1\right)\left(3m-1\right)>0\\m< 0\end{matrix}\right.\Leftrightarrow\left\{{}\begin{matrix}\left[{}\begin{matrix}m>1\\m< \dfrac{1}{3}\end{matrix}\right.\\m< 0\end{matrix}\right.\Leftrightarrow m< 0\)