1, 3/x-7/-12/4x+8/=3x-8
2, -5/x-7/+3/3-x/=12x-8
3, /x-7/ -/3x-5/=0
Các bạn jup mik vs nhé, tl đầy đủ theo cái cách bảng xét dấu thì tốt xg mik tick cho
tìm số nguyên x biết:
a,-5.(-x+7)-3.(-x-5)=-4.(12-x)+48
b;-2.(15-3x)-4.(7x+8)=-5-9.(-2x+1)
c,7.(-x-7)-5.(-x-3)=12.(3-x)
d,5.(-3x-7)-4.(-2x-11)=7.(4x+10)+9
GIÚP MIK VS NHÉ AI LÀM ĐC HẾT MÀ ĐÚNG MIK SẼ CHO 1 TICK
1, 3/x-7/-12/4x+8/=3x-8
2, -5/x-7/+3/3-x/=12x-8
3, /x-7/ -/3x-5/=0
các bạn giúp mik bài này vs
5) (4x-5).(x+2)-(x+5).(x-3)-3x^2-x
6) (x-3).(x+7)-(2x-1).(x+2)+x.(x-1)
7) (7x-3).(2x+1)-(5x-2).(x+4)-9x^2+17x
8) -2.(x-7).(x+3)+(5x-1).(x+4)-3x^2-27x
9) (6x-5).(x+8)-(3x-1).(2x+3)-9.(4x-3)
10) (8x-1).(x+7)-(x-2).(8x+5)-11.(6x+1).
một đòn bẫy dài một mét .đặt ở đâu để có thể dùng 3600n có thể nâng tảng đá nặng 120kg?
Tìm x ( bài tập xoắn 3 đại số 8 )
1. 25x mũ 2 - 20x + 4 = 0
2. ( 2x - 3 ) mũ 2 - ( 2x + 1 ) ( 2x - 1 ) = 0
3. ( 1/2x - 1 ) ( 1/2x + 1 ) - ( 1/2x - 1 ) mũ 2 = 0
4. ( 2x - 3 ) mũ 2 + ( 2x + 5 ) mũ 2 = 8 ( x + 1 ) mũ 2
5. 4x mũ 2 + 12x -7 = 0
6. 1/4x mũ 2 + 2/3x - 5/9 = 0
7. 24 và 8/9 ( hỗn số ) - 1/4x mũ 2 - 1/3x = 0
Các bạn giúp mik nhé, mik sẽ tick cho các bạn !!!!!!!!!!!!
Tìm x:
1. \(25x^2-20x+4=0\)
⇔ \(\left(5x-2\right)^2=0\)
⇔ \(5x-2=0\)
⇔ \(5x=2\)
⇔ \(x=\dfrac{2}{5}\)
⇒ S = \(\left\{\dfrac{2}{5}\right\}\)
2. \(\left(2x-3\right)^2-\left(2x+1\right).\left(2x-1\right)=0\)
⇔ \(4x^2-12x+9-\left(4x^2-1\right)=0\)
⇔ \(4x^2-12x+9-4x^2+1=0\)
⇔ \(-12x+10=0\)
⇔ \(-12x=-10\)
⇔ \(x=\dfrac{5}{6}\)
⇒ S \(=\left\{\dfrac{5}{6}\right\}\)
3. \(\left(\dfrac{1}{2}x-1\right)\left(\dfrac{1}{2}x+1\right)-\left(\dfrac{1}{2}x-1\right)^2=0\)
⇔ \(\dfrac{1}{4}x^2-1-\left(\dfrac{1}{4}x^2-x+1\right)=0\)
⇔ \(\dfrac{1}{4}x^2-1-\dfrac{1}{4}x^2+x-1=0\)
⇔ \(-2+x=0\)
⇔ \(x=2\)
⇒ S \(=\left\{2\right\}\)
4. \(\left(2x-3\right)^2+\left(2x+5\right)^2=8\left(x+1\right)^2\)
⇔ \(4x^2-12x+9+4x^2+20x+25=8\left(x^2+2x+1\right)\)
⇔ \(8x^2+8x+34=8x^2+16x+8\)
⇔ \(8x+34=16x+8\)
⇔ \(8x-16x=8-34\)
⇔ \(-8x=-26\)
⇔ \(x=\dfrac{13}{4}\)
⇒ S \(=\left\{\dfrac{13}{4}\right\}\)
5.\(4x^2+12x-7=0\)
⇔ \(4x^2+14x-2x-7=0\)
⇔ \(2x\left(2x+7\right)-\left(2x+7\right)=0\)
⇔ \(\left(2x+7\right)\left(2x-1\right)=0\)
⇔ \(\left[{}\begin{matrix}2x+7=0\\2x-1=0\end{matrix}\right.\)
⇔ \(\left[{}\begin{matrix}x=\dfrac{-7}{2}\\x=\dfrac{1}{2}\end{matrix}\right.\)
⇒ S \(=\left\{\dfrac{-7}{2};\dfrac{1}{2}\right\}\)
6. \(\dfrac{1}{4}x^2+\dfrac{2}{3}x-\dfrac{5}{9}=0\)
⇔ \(9x^2+24x-20=0\)
⇔ \(9x^2+30x-6x-20=0\)
⇔ \(3x\left(3x+10\right)-2\left(3x+10\right)=0\)
⇔ \(\left(3x+10\right)\left(3x-2\right)=0\)
⇔ \(\left[{}\begin{matrix}3x+10=0\\3x-2=0\end{matrix}\right.\)
⇔ \(\left[{}\begin{matrix}x=\dfrac{-10}{3}\\x=\dfrac{2}{3}\end{matrix}\right.\)
⇒ S \(=\left\{\dfrac{-10}{3};\dfrac{2}{3}\right\}\)
7. \(24\dfrac{8}{9}-\dfrac{1}{4}x^2-\dfrac{1}{3}x=0\)
⇔ \(\dfrac{224}{9}-\dfrac{1}{4}x^2-\dfrac{1}{3}x=0\)
⇔ \(896-9x^2-12x=0\)
⇔ \(-896+9x^2+12x=0\)
⇔ \(9x^2+12x-896=0\)
⇔ \(9x^2-84x+96x-896=0\)
⇔ \(3x\left(3x-28\right)+32\left(3x-28\right)=0\)
⇔ \(\left(3x-28\right)\left(3x+32\right)=0\)
⇔ \(\left[{}\begin{matrix}3x-28=0\\3x+32=0\end{matrix}\right.\)
⇔ \(\left[{}\begin{matrix}x=\dfrac{28}{3}\\x=\dfrac{-32}{3}\end{matrix}\right.\)
⇒ S \(=\left\{\dfrac{-32}{3};\dfrac{28}{3}\right\}\)
1.Tìm x
a)|x-1|+|x+3|=4
b)|2x+3|-2|4-x|=5
c)|x+1|-|x+3|+lx+5|+|x-7|=8
d)|x-2010|+|x-2012|+|x-2014|=2
các bạn làm theo kiểu bảng xét dấu của x
2.Tìm GTNN
A=2|3x-2|-1
B=5|1-4x|-1
C=7+|3-x|
D=|7-x|+|5-xl
E=|7-x|+|5+x|
F=|x+1|+lx+5|
3.Tìm GTLN
A=5-|2x-1|
B=|x+1|-|3+5|
C=|x+5|-|2+x|
D=\(\frac{1}{lx-1l+3}\)
các bạn làm theo dạng bảng xét dấu của x
a,xet cac th sau
x<1'=>1-x+4+x=4=>3-2x=4
=>2x=-1=>x=-1/2
th2 1<x,<5
=>x-1+4+x=4<=>3=4(vo li)
vay x=-1/2
a, 2(x - 5) + 3(2 - 3x) = 5x + 7
b, 3x - 5(x - 2) + 7 = 4x - 12
c, 1/5×8 + 1/8×11 + 1/11×14 +...+ 1/x(x+3) = 101/1540
d, ( 3/1×2×3 + 3/2×3×4 + 3/3×4×5 +...+ 3/8×9×10 ).x = 22/15
Thanks you so much!
Nhớ ghi đầy đủ các bước làm ra nhá!
\(2\left(x-5\right)+3\left(2-3x\right)=5x+7\)
\(\Leftrightarrow2x-10+6-9x=5x+7\)
\(\Leftrightarrow\left(2x-9x\right)+\left(6-10\right)=5x+7\)
\(\Leftrightarrow-7x-4=5x+7\)
\(\Leftrightarrow-7x-5x=4+7\)
\(\Leftrightarrow-12x=11\)
\(\Leftrightarrow x=\frac{-11}{12}\)
\(3x-5\left(x-2\right)+7=4x-12\)
\(\Leftrightarrow3x-5x-10+7=4x-12\)
\(\Leftrightarrow\left(3x-5x\right)-\left(10-7\right)=4x-12\)
\(\Leftrightarrow-2x-3=4x-12\)
\(\Leftrightarrow-2x-4x=3-12\)
\(\Leftrightarrow-6x=-15\)
\(\Leftrightarrow x=\frac{-15}{-6}=\frac{5}{2}\)
\(\frac{1}{5.8}+\frac{1}{8.11}+...+\frac{1}{x\left(x+3\right)}=\frac{101}{1540}\)
\(\Leftrightarrow\frac{3}{5.8}+\frac{3}{8.11}+...+\frac{3}{x\left(x+3\right)}=\frac{101}{1540}.3\)
\(\Leftrightarrow\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+...+\frac{1}{x}-\frac{1}{x+3}=\frac{303}{1540}\)
\(\Leftrightarrow\frac{1}{5}-\frac{1}{x+3}=\frac{303}{1540}\)
\(\Leftrightarrow\frac{5}{5\left(x+3\right)}=\frac{1}{5}-\frac{303}{1540}\)
\(\Leftrightarrow\frac{5}{5x+15}=\frac{308}{1540}-\frac{303}{1540}\)
\(\Leftrightarrow\frac{5}{5x+15}=\frac{5}{1540}\)
\(\Leftrightarrow5x+15=1540\)
\(\Leftrightarrow5x=1540-15\)
\(\Leftrightarrow5x=1525\)
\(\Leftrightarrow x=1525\div5\)
\(\Leftrightarrow x=305\)
Tìm số tự nhiên x biết:
(x+2)-2=0
(x+3)+1=7
(3x-4)+4=12
(5x+4)-1=13
(4x-8)-3=5
8-(2x-4)=2
7+(5x+2)=14
5-(3x-11)=1
Giúp e vs ạ(Vui lòng trình bày ạ)
\(\left(x+2\right)-2=0\)
\(\Rightarrow x+2-2=0\)
\(\Rightarrow x=0\)
\(\left(x+3\right)+1=7\)
\(\Rightarrow x+3+1=7\)
\(\Rightarrow x+4=7\)
\(\Rightarrow x=3\)
\(\left(3x-4\right)+4=12\)
\(\Rightarrow3x-4+4=12\)
\(\Rightarrow3x=12\)
\(\Rightarrow x=4\)
\(\left(5x+4\right)-1=13\)
\(\Rightarrow5x+4-1=13\)
\(\Rightarrow5x+3=13\)
\(\Rightarrow5x=10\)
\(\Rightarrow x=2\)
\(\left(4x-8\right)-3=5\)
\(\Rightarrow4x-8-3=5\)
\(\Rightarrow4x-11=5\)
\(\Rightarrow4x=16\)
\(\Rightarrow x=4\)
\(8-\left(2x+4\right)=2\)
\(\Rightarrow8-2x-4=2\)
\(\Rightarrow4-2x=2\)
\(\Rightarrow2x=2\)
\(\Rightarrow x=1\)
\(7+\left(5x+2\right)=14\)
\(\Rightarrow7+5x+2=14\)
\(\Rightarrow9+5x=14\)
\(\Rightarrow5x=5\)
\(\Rightarrow x=1\)
\(5-\left(3x-11\right)=1\)
\(\Rightarrow5-3x+11=1\)
\(\Rightarrow16-3x=1\)
\(\Rightarrow3x=15\)
\(\Rightarrow x=5\)
Tìm x, biết:
a) (2x+2)(x-1)-(x+2)(2x+1)=0;
b)(3x+1)(2x-3)-6x(x+2)=16;
c)(12x-5)(4x-1)+(3x-7)(1-16x)=81
mn ơi giúp mik vs ạ :<
a: =>2x^2-2x+2x-2-2x^2-x-4x-2=0
=>-5x-4=0
=>x=-4/5
b: =>6x^2-9x+2x-3-6x^2-12x=16
=>-19x=19
=>x=-1
c: =>48x^2-12x-20x+5+3x-48x^2-7+112x=81
=>83x=83
=>x=1
Các bạn giúp mình nhé càng nhanh càng tốt nhà
(5x-1). (2x+3)-3. (3x-1)=0
x^3 (2x-3)-x^2 (4x^2-6x+2)=0
x (x-1)-x^2+2x=5
(3x+2)(x-1)-3 (5x+2)+5 (11-4x)=25
8 (x-2)-2 (3x-4)=25
(3x+4). (5x-1)+(5x+2). (1-3x)+2=0
(5x-1). (2x+7)-(2x-3). (5x+9)
4 (x-1). (X+5)-(x+5). (X+2)=3. (X-1)(x+2)
2x^2+3 (x-1). (X+1)=5x(x+1)
4. (18-5x)-12 (3x-7)=1825. (2x-16)-6 .(x+4)
1/2x. (2/5-4x)+(2x+5).x=-13/2
Nhiều các bạn giả đùm mình nha
Thanh nhiều
+) (5x-1). (2x+3)-3. (3x-1)=0
10x^2+15x-2x-3 - 9x+3=0
10x^2 +8x=0
2x(5x+4)=0
=> x=0 hoặc x= -4/5
+) x^3 (2x-3)-x^2 (4x^2-6x+2)=0
2x^4 -3x^3 -4x^4 + 6x^3 - 2x^2=0
-2x^4 + 3x^3-2x^2=0
x^2(-2x^2+x-2)=0
-2x^2(x-1)^2=0
=> x=0 hoặc x=1
+) x (x-1)-x^2+2x=5
x^2 -x -x^2+2x=5
x=5
+) 8 (x-2)-2 (3x-4)=25
8x - 16-6x+8=25
2x=33
x=33/2