Tìm X:
a. 4/3 x+1/2 = 1/10
b. 2/3 x - 1/2 x = 5/15
c.6/21 ( x - 6/12 )= 2
Đây là phân số
1.a 2 5 1 4 3 10b 8 12 3 7 9 7 c 1 6 x 4 9 5 9 x 1 6 1d 183 93 1 5 2 x 102 1 2 3 4 1 2021 2.a 3 5 x 0,8b 1 4 3 4 x 2 5c x 1 2 8 25 x 1 cái gạch ngang là gạch phân số ạ VD một phần hai 1 2mong mng giúp em sớm ạ
Xin lỗi m.n nhé gửi nhầm tí
2. Tìm x:
a) 4/5 + x = 2/3
b) 1/2 - x = 7/12
c) 3 và 1/2 : x = -7/2
d) 3/8 - 1/6 x =5/2
e) x + 50%x = -1,5
a: x=2/3-4/5=10/15-12/15=-2/15
b: 1/2-x=7/12
=>x=1/2-7/12=-1/12
c: =>7/2:x=-7/2
=>x=-1
d: =>1/6x=3/8-5/2=3/8-20/8=-17/8
=>x=-17/8*6=-102/8=-51/4
e: =>1,5x=-1,5
=>x=-1
Tìm x:
a,(𝑥+2)2+(𝑥+3)2−2(𝑥−2)(𝑥−3)=19
b,(x+2)(x^2-2x+4)-x(x^2-5)=15
c, (x-1)^3+(2-x)(4+2x+x^2)+3x(x+2)=17
\(a,\left(x+2\right)^2+\left(x+3\right)^2-2\left(x-2\right)\left(x-3\right)=19\\ \Leftrightarrow x^2+4x+4+x^2+6x+9-2x^2+10x-12=19\\ \Leftrightarrow20x=20\\ \Leftrightarrow x=1\\ b,\left(x+2\right)\left(x^2-2x+4\right)-x\left(x^2-5\right)=15\\ \Leftrightarrow x^3+8-x^3+5x=15\\ \Leftrightarrow5x=7\\ \Leftrightarrow x=\dfrac{7}{5}\\ c,\left(x-1\right)^3+\left(2-x\right)\left(4+2x+x^2\right)+3x\left(x+2\right)=17\\ \Leftrightarrow x^3-3x^2+3x+1+8-x^3+3x^2+6x=17\\ \Leftrightarrow9x=8\\ \Leftrightarrow x=\dfrac{8}{9}\)
a. (x + 2)2 + (x + 3)2 - 2(x - 2)(x - 3) = 19
<=> (x2 + 4x + 4) + (x2 + 6x + 9) - (2x + 4)(x - 3) = 19
<=> x2 + 4x + 4 + x2 + 6x + 9 - 2x2 + 6x - 4x + 12 = 19
<=> x2 + x2 - 2x2 + 4x + 6x + 6x - 4x + 9 + 4 + 12 - 19 = 0
<=> 12x + 6 = 0
<=> 6(2x + 1) = 0
<=> 2x + 1 = 0
<=> 2x = -1
<=> x = \(\dfrac{-1}{2}\)
b. (x + 2)(x2 - 2x + 4) - x(x2 - 5) = 15
<=> x3 - 2x2 + 4x + 2x2 - 4x + 8 - x3 + 5x - 15 = 0
<=> x3 - x3 - 2x2 + 2x2 + 4x - 4x + 5x + 8 - 15 = 0
<=> 5x - 7 = 0
<=> 5x = 7
<=> x = \(\dfrac{7}{5}\)
Tìm x:
a) (2x - 3)(6 - 2x) = 0
b) \(5\dfrac{4}{7}:x=13\)
c) 2x - \(\dfrac{3}{7}\) = \(6\dfrac{2}{7}\)
d) \(\dfrac{x}{5}\) + \(\dfrac{1}{2}\) = \(\dfrac{6}{10}\)
e) \(\dfrac{x+3}{15}=\dfrac{1}{3}\)
f) \(\dfrac{x-12}{4}=\dfrac{1}{2}\)
g) \(2\dfrac{1}{4}\).\(\left(x-7\dfrac{1}{3}\right)=1,5\)
h) \(\left(4,5-2x\right).1\dfrac{4}{7}=\dfrac{11}{14}\)
i) \(\dfrac{2}{3}\left(x-25\%\right)=\dfrac{1}{6}\)
k) \(\dfrac{3}{2}x-1\dfrac{1}{2}=x-\dfrac{3}{4}\)
a) (2x - 3)(6 - 2x) = 0
=> \(\left[{}\begin{matrix}2x-3=0\\6-2x=0\end{matrix}\right.=>\left[{}\begin{matrix}2x=3\\2x=6\end{matrix}\right.=>\left[{}\begin{matrix}x=\dfrac{3}{2}\\x=3\end{matrix}\right.\)
b) \(5\dfrac{4}{7}:x=13=>\dfrac{39}{7}:x=13=>x=\dfrac{39}{7}:13=>x=\dfrac{3}{7}\)
c) \(2x-\dfrac{3}{7}=6\dfrac{2}{7}=>2x-\dfrac{3}{7}=\dfrac{44}{7}=>2x=\dfrac{47}{7}=>x=\dfrac{47}{14}\)
d) \(\dfrac{x}{5}+\dfrac{1}{2}=\dfrac{6}{10}=>\dfrac{x}{5}=\dfrac{6}{10}-\dfrac{1}{2}=>\dfrac{x}{5}=\dfrac{1}{10}=>x.10=5=>x=\dfrac{1}{2}\)
e) \(\dfrac{x+3}{15}=\dfrac{1}{3}=>\left(x+3\right).3=15=>x+3=5=>x=2\)
f)\(\dfrac{x-12}{4}=\dfrac{1}{2}=\dfrac{x-12}{4}=\dfrac{2}{4}\)
⇒\(x-12=2\)
\(x=2+12\)
x = 14
g)2\(\dfrac{1}{4}.\left(x-7\dfrac{1}{3}\right)=1,5\)
\(\dfrac{9}{4}.\left(x-\dfrac{22}{3}\right)=1,5\)
\(\left(x-\dfrac{22}{3}\right)=\dfrac{3}{2}:\dfrac{9}{4}\)
\(x-\dfrac{22}{3}=\dfrac{2}{3}\)
\(x=\dfrac{2}{3}+\dfrac{22}{3}\)
\(x=8\)
1. Thực hiện phép tính:
a) -1/3 + 7/6 b) 5/7 - 3/5 c) 0,75 . 4/5
2. Tìm x:
a) 4/5 + x = 2/3 b) 1/2 - x = 7/12 c) 3 và 1/2 : x = -7/2 d) 3/8 - 1/6 x =5/2
e) x + 50%x = -1,5
3. Lớp 6H có 40 học sinh gồm 3 loại: giỏi, khá và trung bình. Biết số học sinh giỏi chiếm 1/5 số học sinh cả lớp. Số học sinh còn lại gồm khá và trung bình. Số học sinh trung bình bằng 3/8 số học sinh còn lại.
Hỏi lớp 6H có bao nhiêu học sinh xếp loại giỏi, khá và trung bình?
3: Số học sinh giỏi là 40*1/5=8 bạn
Số học sinh trung bình là 32*3/8=12 bạn
Số học sinh khá là 32-12=20 bạn
1:
a: -1/3+7/6=7/6-2/6=5/6
b: 5/7-3/5=25/35-21/35=4/35
c: 0,75*4/5=4/5*3/4=3/5
tìm x
a,(x+1)^3-(x-1)^3-6(x-1)^2=-10
b,x(x+5)(x-5)-(x+2)(x^2-2x+4)=42
c,(x-2)^3-(x-3)(x^2+3x+9)+6(x+1)^2=49
a) \(\left(x+1\right)^3-\left(x-1\right)^3-6\cdot\left(x-1\right)^2=10\)
\(\Rightarrow x^3+3x^2+3x+1-x^3+3x^2-3x+1-6\cdot\left(x^2-2x+1\right)=10\)
\(\Rightarrow6x^2+2-6x^2+12x-6=10\)
\(\Rightarrow12x-4=10\)
\(\Rightarrow12x=14\)
\(\Rightarrow x=\dfrac{7}{6}\)
b) \(x\left(x+5\right)\left(x-5\right)-\left(x+2\right)\left(x^2-2x+4\right)=42\)
\(\Rightarrow x\left(x^2-25\right)-\left(x^3+8\right)=42\)
\(\Rightarrow x^3-25x-x^3-8=42\)
\(\Rightarrow-25x-8=42\)
\(\Rightarrow-25x=50\)
\(\Rightarrow x=\dfrac{50}{-25}=-2\)
c) \(\left(x-2\right)^3-\left(x-3\right)\left(x^2+3x+9\right)+6\left(x+1\right)^2=49\)
\(\Rightarrow x^3-6x^2+12x-8-\left(x^3-27\right)+6\left(x^2+2x+1\right)=49\)
\(\Rightarrow x^3-6x^2+12x-8-x^3+27+6x^2+12x+6=49\)
\(\Rightarrow24x+25=49\)
\(\Rightarrow24x=24\)
\(\Rightarrow x=\dfrac{24}{24}=1\)
Tìm x:
a, \(\left(12-12\dfrac{1}{3}\right):x+\dfrac{1}{6}=\dfrac{-2}{3}\)
b, \(\dfrac{4}{x}=\dfrac{x}{16}\)
a) \(\left(12-12\dfrac{1}{3}\right):x+\dfrac{1}{6}=-\dfrac{2}{3}\)
\(-\dfrac{1}{3}x=-\dfrac{2}{3}-\dfrac{1}{6}\)
\(-\dfrac{1}{3}x=-\dfrac{5}{6}\)
\(x=-\dfrac{5}{6}:\left(-\dfrac{1}{3}\right)\)
\(x=\dfrac{5}{2}\)
b) \(\dfrac{4}{x}=\dfrac{x}{16}\)
\(x^2=4.16\)
\(x^2=64\)
\(\Rightarrow x=8;x=-8\)
`a)=>(12-37/3):x+1/6=-2/3`
`=>(12-37/3):x=-5/6`
`=>(-1/3):x=-5/6`
`=>x=(-1/3):(-5/6)`
`=>x=6/15=2/5`
`b)4/x=x/16`
`=>x^2=4*16`
`=>x^2=64`
`=>x^2=(+-8)^2`
Tìm x:
a) 3/4 x X = 5/8
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b) 5/6 - X = 1/ 12
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a)x=\(\dfrac{5}{8}:\dfrac{3}{4}=\dfrac{5}{6}\)
b) x=\(\dfrac{5}{6}-\dfrac{1}{12}=\dfrac{3}{4}\)
a \(x=\dfrac{5}{8}:\dfrac{3}{4}\)
\(x=\dfrac{5}{8}\times\dfrac{4}{3}\)
\(x=\dfrac{5}{6}\)
b \(x=\dfrac{5}{6}-\dfrac{1}{12}\)
\(x=\dfrac{10}{12}-\dfrac{1}{12}\)
\(x=\dfrac{9}{12}\)
\(x=\dfrac{3}{4}\)
Tìm x:
a) 4.(2-x)+x.(x+6)=x2
b) x.(x-7)-(x-2).(x+5)=0
c) (2x+3).(3-2x)+(2x-1)2=2
a: Ta có: \(4\left(2-x\right)+x\left(x+6\right)=x^2\)
\(\Leftrightarrow8-4x+x^2+6x-x^2=0\)
\(\Leftrightarrow2x=-8\)
hay x=-4
b: Ta có: \(x\left(x-7\right)-\left(x-2\right)\left(x+5\right)=0\)
\(\Leftrightarrow x^2-7x-x^2-3x+10=0\)
\(\Leftrightarrow-10x=-10\)
hay x=1
c: Ta có: \(\left(2x+3\right)\left(3-2x\right)+\left(2x-1\right)^2=2\)
\(\Leftrightarrow9-4x^2+4x^2-4x+1=2\)
\(\Leftrightarrow-4x=-8\)
hay x=2