(x-3).(x+3)- (x-6)^2
(x+1)^2+(x-1)^2- (x-1).(x-1)
(x+4).(x-4).(x^2+16)
(2+1).(2^2+1).(2^4+1).(2^8+1)
Giúp mình với ạ!
Tìm x:
a) 2 3/4 - x=3/4
b) x:5/6=-3/5
c)1 1/3 +2/3:x=1
d) x-1/9=8/3
e) 1/2 x + 650%x-x= -6
g) 2(x - 1/2) + 3(-1+x/3)=x(2/x - 1) (x khác 0)
h) x-2/20= -5/2-x
i) (x/2-1)3 + 2=-11/8
k) (x/3 +1/2) (75% - 1 1/2x)=0
GIÚP MÌNH VỚI Ạ. CẢM ƠN MỌI NGƯỜI!
a) \(2\dfrac{3}{4}-x=\dfrac{3}{4}\)
\(\Rightarrow\dfrac{11}{4}-x=\dfrac{3}{4}\)
\(\Rightarrow x=\dfrac{11}{4}-\dfrac{3}{4}=\dfrac{8}{4}=2\)
b) \(x:\dfrac{5}{6}=-\dfrac{3}{5}\)
\(\Rightarrow x=-\dfrac{3}{5}.\dfrac{5}{6}=-\dfrac{15}{30}=-\dfrac{1}{2}\)
c) \(1\dfrac{1}{3}+\dfrac{2}{3}:x=1\)
\(\Rightarrow\dfrac{2}{3}:x=1-1\dfrac{1}{3}\)
\(\Rightarrow\dfrac{2}{3}:x=-\dfrac{1}{3}\)
\(\Rightarrow x=\dfrac{2}{3}:-\dfrac{1}{3}\)
\(\Rightarrow x=-2\)
d) \(x-\dfrac{1}{9}=\dfrac{8}{3}\)
\(\Rightarrow x=\dfrac{8}{3}+\dfrac{1}{9}\)
\(\Rightarrow x=\dfrac{25}{9}\)
e) \(\dfrac{1}{2}x+650\%x-x=-6\)
\(\Rightarrow\dfrac{1}{2}x+\dfrac{13}{2}x-x=-6\)
\(\Rightarrow x\left(\dfrac{1}{2}+\dfrac{13}{2}-1\right)-6\)
\(\Rightarrow6x=-6\)
\(\Rightarrow x=\dfrac{-6}{6}=-1\)
g) \(2\left(x-\dfrac{1}{2}\right)+3\left(-1+\dfrac{x}{3}\right)=x\left(\dfrac{2}{x}-1\right)\) \(\text{Đ}K:x\ne0\)
\(\Rightarrow2x-1-3+x=2-x\)
\(\Rightarrow3x-4=2-x\)
\(\Rightarrow3x+x=2+4\)
\(\Rightarrow4x=6\)
\(\Rightarrow x=\dfrac{6}{4}=\dfrac{3}{2}\)
h) \(x-\dfrac{2}{20}=-\dfrac{5}{2}-x\)
\(\Rightarrow x+x=-\dfrac{5}{2}+\dfrac{2}{20}\)
\(\Rightarrow2x=-\dfrac{12}{5}\)
\(\Rightarrow x=-\dfrac{12}{5}:2=-\dfrac{6}{5}\)
i) \(\left(\dfrac{x}{2}-1\right)^3+2=-\dfrac{11}{8}\)
\(\Rightarrow\left(\dfrac{x}{2}-1\right)^3=-\dfrac{11}{8}-2\)
\(\Rightarrow\dfrac{x}{2}-1=\sqrt[3]{-\dfrac{27}{8}}\)
\(\Rightarrow\dfrac{x}{2}-1=-\dfrac{3}{2}\)
\(\Rightarrow\dfrac{x}{2}=-\dfrac{3}{2}+1\)
\(\Rightarrow x=-\dfrac{1}{2}.2=-1\)
k) \(\left(\dfrac{x}{3}+\dfrac{1}{2}\right)\left(75\%-1\dfrac{1}{2}x\right)=0\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{x}{3}+\dfrac{1}{2}=0\\\dfrac{3}{4}-1\dfrac{1}{2}x=0\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}\dfrac{x}{3}=-\dfrac{1}{2}\\\dfrac{3}{2}x=\dfrac{3}{4}\end{matrix}\right.\)
\(\Leftrightarrow\left[{}\begin{matrix}x=-\dfrac{1}{2}.3=-\dfrac{3}{2}\\x=\dfrac{3}{4}:\dfrac{3}{2}=\dfrac{1}{2}\end{matrix}\right.\)
TÌM X
câu 1: (1/3 + 1/6) . 2^x+3 - 2^x = 2^22 - 2^20
câu 2: (1/2-1/6).3^x+3^x+2=3^16+3^13
câu 3: (1/2 - 1/6) . 3^x+4 - 4 . 3^x = 3^16 - 4 . 3^13
mình cần gấp. mn lm ơn giúp mifh vs ạ. !!!huhuhu
16/ 1/2.x+1/6.x(x-2)=3/4-2.x
19/ 5/12.x+3=1/3-7/12.x
20/ 1/2.x+5/2=7/2.x-3/4
Mọi người giúp mình với mình đang cần gấp!!!
rút gọn biểu thức
(x-3).(x+3)-(x-6)^2
(x+1)^2+(x-1)^2-(x-1).(x+1)
(x+4).(x-4).(x^2+16)
(2+1).(2^2+1).(2^4+1).(2^8+1)
Giúp mình với ạ!
1) 5+10+15+...+195 -2 * x =3270
2) (X+1) +(X4) +(X+7)+....+(X+28) =155
3)1/2 * X 1/6 *X=2/3
4)X04 + 40X = 101 *11
5) (X+1/2) +(X+1/4) +(X+1/8) +(X+1/16)=1
tìm x nhé giúp mình với
Bài 299: Tính
1) 1/3 x 1/2 x 3/7
2) 5/4 x 1/3 + 1/7
3) 8 x ( 8/9-2/3 )
4) 5/6 x 48/20 x 1/2
5) ( 2/5 + 3/4 + x 8
6) 10 x ( 1/2 - 1/5 )
Trình bày rõ cách làm giúp ạ!!
1) 1/3 x 1/2 x 3/7 = 3/42 = 1/14
2) 5/4 x 1/3 +1/7 = 5/12 + 1/7 = 35/84 + 12/84 = 47/84
3) 8 x ( 8/9 - 2/3 ) = 8 x 2/9 = 16/9
4) 5/6 x 48/20 x 1/2 = 240/240 = 1
5) ( 2/5 + 3/4 ) + 8 = 23/20 + 8 = 23//20 + 160/20 = 183/20
6) 10 x ( 1/2 - 1/5 ) = 10 x 3/10 = 10/1 x 3/10 = 30/10 = 3
bài1: a)x:1/2+x:1/4+x:1/8+x:1/10=1
b)x*4+x:4+x:2=19
c)x+x*1/3:1/9+x:2/7=252
d)x+x:2+x:3+x:4=25/12
bài2: a)1/2+1/6+1/2+...+1/y*(y+1)=16/16
b)1/1*2+1/2*3+1/3*4+...+1/x*(x+1)=996/997
c)(x+1)+(x+2)+(x+3)+...+(x+50)=2275
d)1/3+1/6+1/10+...+1/x+(x+1):2=2009/2011
cứu mình với
ai trả lời nhanh nhất mình tick cho :)
mai mình phải nộp bài rồi
giúp mình 3 câunày với ạ . tuần sau mình cần nộp
a) 2\(^2\).16 ≥ \(2^x\) ≥ \(4^2\)
b) 9.27 ≤ \(3^x\) ≤ 243
c) 2. \(\left(x-\dfrac{1}{2}\right)^2\) \(-\dfrac{1}{8}\) = 0
`@` `\text {Ans}`
`\downarrow`
`a)`
`2^2 * 16 \ge 2^x \ge 4^2`
`=> 2^2 * 2^4 \ge 2^x \ge 2^4`
`=> 2^6 \ge 2^x \ge 2^4`
`=> x \in {4; 5; 6}`
`b)`
`9*27 \le 3^x \le 243`
`=> 3^2 * 3^3 \le 3^x \le 3^5`
`=> 3^5 \le 3^x \le 3^5`
`=> x = 5`
`c)`
`2 * (x - 1/2)^2 - 1/8 = 0`
`=> 2* (x - 1/2)^2 = 1/8`
`=> (x - 1/2)^2 = 1/8 \div 2`
`=> (x-1/2)^2 = 1/16`
`=> (x - 1/2)^2 = (+- 1/4)^2`
`=>`\(\left[{}\begin{matrix}x-\dfrac{1}{2}=\dfrac{1}{4}\\x-\dfrac{1}{2}=-\dfrac{1}{4}\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=\dfrac{1}{4}+\dfrac{1}{2}\\x=\dfrac{1}{2}-\dfrac{1}{4}\end{matrix}\right.\)
`=>`\(\left[{}\begin{matrix}x=\dfrac{3}{4}\\x=\dfrac{1}{4}\end{matrix}\right.\)
Vậy, `x \in {1/4; 3/4}.`
Tìm các số nguyên x;y biết
a) -5/8=x/16 ; 3x/9=2/6
b) x+3/15=1/3 ; 6/2x+1=2/7
c)4/x-6=y/24=-12/18 ; 3-x/-12=16/y+1=192/-72
d)-2/3<x/5<-1/6 ; -1/5<(hoặc =)x/8<(hoặc =)1/4
e)x+46/20=x 2/5 ; y 5/y=86/y
(Lưu ý: x 2/5;y 5/y là các số hỗn)
Giúp mình với,cảm ơn nhìu :33 moazz!
Giải:
a) \(\dfrac{-5}{8}=\dfrac{x}{16}\)
\(\Rightarrow x=\dfrac{16.-5}{8}=-10\)
\(\dfrac{3x}{9}=\dfrac{2}{6}\)
\(\Rightarrow3x=\dfrac{2.9}{6}=3\)
\(\Rightarrow x=1\)
b) \(\dfrac{x+3}{15}=\dfrac{1}{3}\)
\(\Rightarrow x+3=\dfrac{1.15}{3}=5\)
\(\Rightarrow x=2\)
\(\dfrac{6}{2x+1}=\dfrac{2}{7}\)
\(\Rightarrow2x+1=\dfrac{6.7}{2}=21\)
\(\Rightarrow x=10\)
c) \(\dfrac{4}{x-6}=\dfrac{y}{24}=\dfrac{-12}{18}\)
\(\Rightarrow\dfrac{4}{x-6}=\dfrac{-12}{18}\)
\(\Rightarrow x-6=\dfrac{18.4}{-12}=-6\)
\(\Rightarrow x=0\)
\(\Rightarrow\dfrac{y}{24}=\dfrac{-12}{18}\)
\(\Rightarrow y=\dfrac{-12.24}{18}=-16\)
\(\dfrac{3-x}{-12}=\dfrac{16}{y+1}=\dfrac{192}{-72}\)
\(\Rightarrow\dfrac{3-x}{-12}=\dfrac{192}{-72}\)
\(\Rightarrow3-x=\dfrac{192.-12}{-72}=32\)
\(\Rightarrow x=-29\)
\(\Rightarrow\dfrac{16}{y+1}=\dfrac{192}{-72}\)
\(\Rightarrow y+1=\dfrac{16.-72}{192}=-6\)
d) \(\dfrac{-2}{3}< \dfrac{x}{5}< \dfrac{-1}{6}\)
\(\Rightarrow\dfrac{-20}{30}< \dfrac{6x}{30}< \dfrac{-5}{30}\)
\(\Rightarrow6x\in\left\{-18;-12;-6\right\}\)
\(\Rightarrow x\in\left\{-3;-2;-1\right\}\)
\(\dfrac{-1}{5}\le\dfrac{x}{8}\le\dfrac{1}{4}\)
\(\Rightarrow\dfrac{-8}{40}\le\dfrac{5x}{40}\le\dfrac{10}{40}\)
\(\Rightarrow5x\in\left\{-5;0;5;10\right\}\)
\(\Rightarrow x\in\left\{-1;0;1;2\right\}\)
e) \(\dfrac{x+46}{20}=x\dfrac{2}{5}\)
\(\Rightarrow\dfrac{x+46}{20}=x+\dfrac{2}{5}\)
\(\Rightarrow\dfrac{x+46}{20}=\dfrac{5x+2}{5}\)
\(\Rightarrow5.\left(x+46\right)=20.\left(5x+2\right)\)
\(\Rightarrow5x+230=100x+40\)
\(\Rightarrow5x-100x=40-230\)
\(\Rightarrow-95x=-190\)
\(\Rightarrow x=-190:-95\)
\(\Rightarrow x=2\)
\(y\dfrac{5}{y}=\dfrac{86}{y}\)
\(\Rightarrow y+\dfrac{5}{y}=\dfrac{86}{y}\)
\(\Rightarrow\dfrac{y^2+5}{y}=\dfrac{86}{y}\)
\(\Rightarrow y^2+5=86\)
\(\Rightarrow y^2=86-5\)
\(\Rightarrow y^2=81\)
\(\Rightarrow\left[{}\begin{matrix}y=9\\y=-9\end{matrix}\right.\)
Chúc bạn học tốt!