tim x,y thuoc Z
a)5x.(-x)^2+1=6
4.x^3=4x
xy=x+y
xy=x-y
giai giup mik nha mik can gap
cho cac tap hop
A= { x thuoc Z / -3<x nho hon bang 7}
B = {x thuoc Z /3 nho hon bang |x| <7 }
C = { x thuoc Z / |x| < 5}
Tim A giaoB; B giao C ; C giao A
B hop C ; A hop C
LAM NHANH HO MIK NHA MIK CAN GAP !PLEASE! AI LAM TRA LOI NHANH MIK TICK CHO
tim giá trị nho nhât
a) x^2-4x+5
b)x^2+y^2-8x+4y+2016
c) x^2+y^2-xy-x+y+1
GIUP MIK VS NHA
CAN GAP
a) = x2 -4x + 4+1 = (x-2)2 +1
GYNN = 1
B) = (x2 - 8x +16) + ( y2 +4y +4) + 2016 -16 -4
= (x - 4)2 + ( y +2)2 + 1996
GTNN = 1996
c) =(x-y)2 +xy -x +y +1 hình như câu này bn chép sai đề nên k có GTNN
( ĐÂY là những bài khó , có thể bn k hiu nhưng đúng 100%, bn cứ chép ra lop thầy giảng cho)
câu c) có thể là y-1 mà bn nhầm y+1
tim x biet N thuoc
a) 2-(x+3)=1+2+3+4+5+..............+99
b)(x+1)+(x+2)+(x+3)+(x+4)+...............+(x+100)=5750
giup mk nha cac ban , mk dang can gap lam
a) 2-(x+3) = 1+2+3+...+99
1+2+3+...+99 → có 99 số hạng
2-(x+3) = (1+99).99 : 2
2-(x+3) = 4950
x+3 = 2 + 4950
x+3 = 4952
x = 4952 - 3
x = 4949
b) (x+1)+(x+2)+...+(x+100) = 5750
→ có 100 cặp
(x+x+x+...+x) + ( 1+2+3+...+100 ) = 5750
=> 100x + 5050 = 5750
100x = 5750 - 5050
100x = 700
x = 700 : 100
x = 7
0o0 Nguyễn Đoàn Tuyết Vy 0o0 bà kêu tui học tốt có nghĩa là học giốt đúng ko
b)(x+1)+(x+2)+(x+3)+(x+4)+...............+(x+100)=5750
(x+x+x+x+...+x) + (1+2+3+4+...+100) = 5750
100x + 5050 = 5750
100x = 5750 - 5050
100x = 700
x = 700 : 100
x = 7
Vậy ...
1 tim x , biet
a) x - 7va 5/8 = 1 va 1/4
b) x + 7 va 5/8 = 9 va 1/4
c) ( x - 7 va 5/8 ) : 1/2 = 3
d) x / 1x3 + x/3x5+.....+x/97x99=99
giup mik nhanh nha . mik can gap lam
\(a,x-7\frac{5}{8}=1\frac{1}{4}\)
=> \(x-\frac{61}{8}=\frac{5}{4}\)
=> \(x=\frac{5}{4}+\frac{61}{8}\)
=> \(x=\frac{10}{8}+\frac{61}{8}=\frac{71}{8}=8\frac{7}{8}\)
\(b,x+7\frac{5}{8}=9\frac{1}{4}\)
=> \(x+\frac{43}{5}=\frac{37}{4}\)
=> \(x=\frac{37}{4}-\frac{43}{5}=\frac{13}{20}\)
\(c,\left[x-7\frac{5}{8}\right]:\frac{1}{2}=3\)
=> \(\left[x-\frac{61}{8}\right]=3\cdot\frac{1}{2}\)
=> \(\left[x-\frac{61}{8}\right]=\frac{3}{2}\)
=> \(x-\frac{61}{8}=\frac{3}{2}\)
=> \(x=\frac{3}{2}+\frac{61}{8}=\frac{12}{8}+\frac{61}{8}=\frac{73}{8}=9\frac{1}{8}\)
d, \(\frac{x}{1\cdot3}+\frac{x}{3\cdot5}+\frac{x}{5\cdot7}+...+\frac{x}{97\cdot99}=99\)
=> \(\frac{x}{2}\left[\frac{2}{1\cdot3}+\frac{2}{3\cdot5}+\frac{2}{5\cdot7}+...+\frac{2}{97\cdot99}\right]=99\)
=> \(\frac{x}{2}\left[1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{97}-\frac{1}{99}\right]=99\)
=> \(\frac{x}{2}\left[1-\frac{1}{99}\right]=99\)
=> \(\frac{x}{2}\cdot\frac{98}{99}=99\)
=> \(\frac{98x}{198}=99\)
=> 98x = 99 . 198
=> 98x = 19602
=> x = 19602 : 98 = 9801/49
a) \(x-7\frac{5}{8}=1\frac{1}{4}\)
=> \(x=\frac{5}{4}+\frac{61}{8}\)
=> \(x=\frac{71}{8}\)
b) \(x+7\frac{5}{8}=9\frac{1}{4}\)
=> \(x=\frac{37}{4}-\frac{61}{8}\)
=> \(x=\frac{13}{8}\)
c) \(\left(x-7\frac{5}{8}\right):\frac{1}{2}=3\)
=> \(x-\frac{61}{8}=3.\frac{1}{2}\)
=> \(x-\frac{61}{8}=\frac{3}{2}\)
=> \(x=\frac{3}{2}+\frac{61}{8}\)
=> \(x=\frac{73}{8}\)
d) \(\frac{x}{1.3}+\frac{x}{3.5}+...+\frac{x}{97.99}=99\)
=> \(x.\frac{1}{2}.\left(\frac{2}{1.3}+\frac{2}{3.5}+...+\frac{2}{97.99}\right)=99\)
=> \(\frac{1}{2}x\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+....+\frac{1}{97}-\frac{1}{99}\right)=99\)
=> \(x\left(1-\frac{1}{99}\right)=99:\frac{1}{2}\)
=> \(x.\frac{98}{99}=198\)
=> \(x=198:\frac{98}{99}=\frac{9801}{49}\)
\(b,\text{ }x+7\frac{5}{8}=9\frac{1}{4}\)
\(x=9\frac{1}{4}-\left(7+\frac{5}{8}\right)\)
\(x=9+\frac{1}{4}-7-\frac{5}{8}\)
\(x=\left(9-7\right)+\left(\frac{1}{4}-\frac{5}{8}\right)\)
\(x=2+-\frac{3}{8}\)
\(x=2\frac{-3}{8}\)
A=1(x+3) - | 3x+2 |
a)rut gon A
b)tim x de A=5
Mik can rat gap giup mik di mik tick cho :(
a)th1:x+3-3x+2=(-2x)+5
th2:x+3+3x+2=4x+5
b)x=0
Tim \(x\in Z\)biet :
a; \(-12\times\left(x-5\right)+7\times\left(3-x\right)=20\)
b; 30\(30\times\left(x+1\right)-3\times\left(x-5\right)-15x=25\)
c; \(|5x-2|\le13\)
mn la on gip mik nha mik dang can gap
a,-12(x-5)+7(3-x)=20
-12x+60+21-7x=20
-19x=-61
x=\(\frac{61}{19}\)
b,30(x+1)-3(x-5)-15x=25
30x+30+15-3x-15x=25
12x=-20
x=\(-\frac{20}{12}\)
giai ho mik nha mik can gap
tim x
2x+1-3=13
(x+1)3+3=30
2x+1-3=13
2x+1=13+3
2x+1=16
2x+1=24
Vậy x+1=4
x=4-1=3
Vậy x=3
a) 2x+1-3=13
2x+1=13+3
2x+1=16
2x+1=24
Vậy x+1=4
x=4-1=3
Vậy x=3
b) (x+1)3+3=30
(x+1)3 = 30 - 3
(x+1)3 = 27 = 33
=> x+1 = 3
x = 3 - 1
x = 2
Vậy x = 2
TICK MK NHA
2\(^{x+1}\) - 3 = 13
\(\Rightarrow2^{x+1}=16\) \(\Rightarrow2x.2=16\) \(\Rightarrow\) 2x = 8 \(\Rightarrow\) x = 4
( x + 1 ) \(^3\) + 3 = 30
\(\Rightarrow\) \(\)\(\left(x+1\right)^3=27\)
3\(^3\) = 27
\(\Rightarrow x+1=3\Rightarrow x=2\)
Tim x, y, z biet :
a , x/5 = y/7 va x . y =140
b , x : y : z = 2 : 5 : 7 va 3x + 2y - z =27
Moi nguoi giup minh giai bai nay nha minh can gap
a) Đặt \(\frac{x}{5}=\frac{y}{7}=k\)
\(\Rightarrow\hept{\begin{cases}x=5k\\y=7k\end{cases}}\)
\(\Rightarrow xy=5k.7k\)
\(\Rightarrow140=35k^2\)
\(\Rightarrow k^2=4\)
\(\Rightarrow\orbr{\begin{cases}k=2\\k=-2\end{cases}}\)
Với k = 2 ta có :
+) \(\frac{x}{5}=2\Rightarrow x=10\)
+) \(\frac{y}{7}=2\Rightarrow y=14\)
Với k = -2 ta có :
+) \(\frac{x}{5}=-2\Rightarrow x=-10\)
+) \(\frac{y}{7}=-2\Rightarrow y=-14\)
Vậy \(\left(x;y\right)=\left\{\left(10;14\right);\left(-10;-14\right)\right\}\)
b) Ta có :
\(x:y:z\)\(=\)\(2:5:7\)\(\Rightarrow\)\(\frac{x}{2}=\frac{y}{5}=\frac{z}{7}\)\(\Rightarrow\)\(\frac{3x}{6}=\frac{2y}{10}=\frac{z}{7}\)
Áp dụng tính chất của dãy tỉ số bằng nhau ta có :
\(\frac{3x}{6}=\frac{2y}{10}=\frac{z}{7}=\frac{3x+2y-z}{6+10-7}=\frac{27}{9}=3\)
+) \(\frac{x}{2}=3\Rightarrow x=6\)
+) \(\frac{y}{5}=3\Rightarrow y=15\)
+) \(\frac{z}{7}=3\Rightarrow z=21\)
Vậy x = 6, y = 15 và z = 21
_Chúc bạn học tốt_
a, x.y/5.7=140/35
=140/35=4
x/5=4/7
x/7=5/4
x.7=5.4
x.7=20
x=20;7
x=20/7
b,chịu
tk thì tk ko tk cx đc
a, \(\frac{x}{5}=\frac{y}{7}\left(x.y=140\right)\)
Đặt \(\frac{x}{5}=\frac{y}{7}=k\)
\(\Rightarrow7x=5y\)
\(\Rightarrow x.y=7k.5k=35k^2=140\)
\(\Rightarrow k^2=4\Rightarrow k=\pm2\)
\(\Rightarrow\orbr{\begin{cases}\hept{\begin{cases}x=2.7=14\\y=2.5=10\end{cases}}\\\hept{\begin{cases}x=\left(-2\right).7=-14\\y=\left(-2\right).5=-10\end{cases}}\end{cases}}\)\(\Rightarrow\orbr{\begin{cases}\hept{\begin{cases}x=2.7=14\\y=2.5=10\end{cases}}\\\hept{\begin{cases}x=\left(-2\right).7=-14\\y=\left(-2\right).5=-10\end{cases}}\end{cases}}\)
Vậy ....
b, \(x:y:z=2:5:7\left(3x+2y-z=27\right)\)
Đặt \(\frac{x}{2}=\frac{y}{5}=\frac{z}{7}=k\)
\(\Leftrightarrow x=2k;y=5k=z=7k\)
\(\Leftrightarrow3x+2y-z=6k+10k-7k=27\)
\(\Leftrightarrow x=6;y=15;z=21\)
Vậy ...
tim n thuoc Z 3n-1 chia het cho 2-n
giai nhanh giup mik,mik can gap,cieu phai nop bai roi