x+3=5 tìm x
1) tìm số nguyên x để 4x-6/ 2x+1
2) Tìm x thuộc z để: 3.(x - 3).(x + 5)< 0
3 tìm x
1/3-(2/3-x + 5/4= 7/12 -(5/2 - 13/6)
\(\frac{1}{3}-\left(\frac{2}{3}-x+\frac{5}{4}\right)=\frac{7}{12}-\left(\frac{5}{2}-\frac{13}{6}\right)\)
\(\frac{1}{3}-\left(\frac{2}{3}-x+\frac{5}{4}\right)=\frac{7}{12}-\frac{1}{3}\)
\(\frac{1}{3}-\left(\frac{2}{3}-x+\frac{5}{4}\right)=\frac{1}{4}\)
\(\frac{2}{3}-x+\frac{5}{4}=\frac{1}{3}-\frac{1}{4}\)
\(\frac{2}{3}-x+\frac{5}{4}=\frac{1}{12}\)
\(\frac{2}{3}-x=\frac{1}{12}-\frac{5}{4}\)
\(\frac{2}{3}-x=-\frac{7}{6}\)
\(x=\frac{2}{3}-\left(-\frac{7}{6}\right)\)
\(x=\frac{2}{3}+\frac{7}{6}\)
\(x=\frac{11}{6}\)
BÀI 3 : Tìm số nguyên x, biết
a, 5/8= x14 x/6= 1/-3 3/-5= x/10 3/5= -9/11
x/2= 2/x x/-5= -5/x
\(a,\dfrac{5}{8}=\dfrac{x}{14}\)
\(\Rightarrow x=\dfrac{5.14}{8}=8,75\)
Vậy \(x=8,75\)
\(b,\dfrac{x}{6}=-\dfrac{1}{3}\)
\(\Rightarrow x=-\dfrac{1.6}{3}=-2\)
Vậy \(x=-2\)
\(c,-\dfrac{3}{5}=\dfrac{x}{10}\)
\(\Rightarrow x=-\dfrac{3.10}{5}=-6\)
Vậy \(x=-6\)
câu d đã có đáp án
\(+\text{)}\dfrac{5}{8}=14x\)⇒\(x=\dfrac{5}{112}\)
\(+\text{)}\dfrac{x}{6}=-\dfrac{1}{3}\)⇒\(x=-2\)
\(+\text{)}-\dfrac{3}{5}=\dfrac{x}{10}\)⇒\(x=-6\)
\(+\text{)}\dfrac{3}{5}=-\dfrac{9}{11}\)⇒\(\dfrac{33}{55}=\dfrac{45}{55}\)
\(+\text{)}\dfrac{x}{2}=\dfrac{2}{x}\)⇒\(x=+-2\)
\(+\text{)}\dfrac{x}{-5}=\dfrac{-5}{x}\)⇒\(x=+-5\)
tìm X
X - 6/5 = 3/4 : 3/16 X x 4/5 = 3/4 + 2/5
X - 6/5 = 4
X = 4 + 6/5
X= 26/5
X x 4/5 = 23/20
X = 23/20 : 4/5
X = 23/16
1) tìm x: 52x-3 – 2.58 = 3.58
2) tìm x: (3x - 2) - (2x + 5) = -7
3) tìm x: 5x - 13 = - 49 - 4x.
4)tìm x: x + ( x +1) + ( x + 2) + …+ ( x + 30) = 496
5) tìm x: 3x + 3x+2 = 810
6) Tìm các số nguyên x, y thỏa mãn: 3xy + x + 3y = 4
Tìm x :
1 / 3 x + 5 / 3 x + x = - 5 / 7
\(\Rightarrow\dfrac{1}{3}x+\dfrac{5}{3}x+1x=\dfrac{-5}{7}\\ x\cdot\left(\dfrac{1}{3}+\dfrac{5}{3}+1\right)=\dfrac{-5}{7}\\ x\cdot3=\dfrac{-5}{7}\\ x=\dfrac{-5}{21}\)
\(\dfrac{1}{3}x+\dfrac{5}{3}x+x=-\dfrac{5}{7}\)
\(\left(\dfrac{1}{3}+\dfrac{5}{3}+1\right)x=-\dfrac{5}{7}\)
\(\left(\dfrac{1}{3}+\dfrac{5}{3}+\dfrac{3}{3}\right)x=-\dfrac{5}{7}\)
\(3x=-\dfrac{5}{7}\)
\(\Rightarrow x=-\dfrac{5}{7}:3\)
\(\Rightarrow x=-\dfrac{5}{7}.\dfrac{1}{3}\)
\(\Rightarrow x=-\dfrac{5}{21}\)
Bài 1 tìm A khi A = x + |10| và x = 28
Bài 2 tính | -3 + (17) |
|3| + |17|
Bài 3 tìm * khi |-5*| + |25| = -80
Bài 4 cho tổng S = |-1| + |-3| + |-5| + x = -14 tìm x
Bài 5 tìm x khi |-2| + |-3| < x < -1
Thay x=28 và A=x+|10|
ta có
A=28+|10|
A=28+10
A=38
a) tìm x biết |x-5|-x=3
b) tìm giá trị nhỏ nhất của bt A=|x-1|+|3-x|+|x-5|
a)\(\left|x-5\right|-x=3\)
\(TH1:x-5-x=3\)
\(-5=3\)(ko xảy ra)
\(xkoTM\)
\(TH2:-\left(x-5\right)-x=3\)
\(5-x-x=3\)
\(5-2x=3\)
\(2x=2\)
x=1
Vậy x=1
tìm x , biết
a) 17/6- x( x-7/6)= 7/4
b) 3/35 - ( 3/5-x)= 2/7
tìm x thuộc Z , biết
3/4-5/6 < x/12 < 1 -( 2/3-1/4)
tìm x biết
a ) 2x-3=x + 1/2
b) 4x- ( x+ 1/2) = 2x - ( 1/2 - 5 )
Bài 1:
a) Ta có: \(\dfrac{17}{6}-x\left(x-\dfrac{7}{6}\right)=\dfrac{7}{4}\)
\(\Leftrightarrow\dfrac{17}{6}-x^2+\dfrac{7}{6}x-\dfrac{7}{4}=0\)
\(\Leftrightarrow-x^2+\dfrac{7}{6}x+\dfrac{13}{12}=0\)
\(\Leftrightarrow-12x^2+14x+13=0\)
\(\Delta=14^2-4\cdot\left(-12\right)\cdot13=196+624=820\)
Vì Δ>0 nên phương trình có hai nghiệm phân biệt là:
\(\left\{{}\begin{matrix}x_1=\dfrac{14-2\sqrt{205}}{-24}=\dfrac{-7+\sqrt{205}}{12}\\x_2=\dfrac{14+2\sqrt{2015}}{-24}=\dfrac{-7-\sqrt{205}}{12}\end{matrix}\right.\)
b) Ta có: \(\dfrac{3}{35}-\left(\dfrac{3}{5}-x\right)=\dfrac{2}{7}\)
\(\Leftrightarrow\dfrac{3}{5}-x=\dfrac{3}{35}-\dfrac{10}{35}=\dfrac{-7}{35}=\dfrac{-1}{5}\)
hay \(x=\dfrac{3}{5}-\dfrac{-1}{5}=\dfrac{3}{5}+\dfrac{1}{5}=\dfrac{4}{5}\)
Bài 3:
a) Ta có: \(2x-3=x+\dfrac{1}{2}\)
\(\Leftrightarrow2x-x=\dfrac{1}{2}+3\)
\(\Leftrightarrow x=\dfrac{7}{2}\)
b) Ta có: \(4x-\left(x+\dfrac{1}{2}\right)=2x-\left(\dfrac{1}{2}-5\right)\)
\(\Leftrightarrow3x-\dfrac{1}{2}-2x+\dfrac{1}{2}-5=0\)
\(\Leftrightarrow x=5\)
tìm x :
A, (2x+1)^3=2^3 . 5^2 - 75
B, tìm x, y là số nguyên : x . Y - x + y = 4
C, tìm x, y là số tự nhiên : 5^x+12^y=26
a: \(\Leftrightarrow\left(2x+1\right)^3=8\cdot25-75=125\)
=>2x+1=5
hay x=2
c: x=2; y=0
Tìm x biết
a,2/3.x+1/3=1/5
b,4/5- 5/3.x=-2
c,1/5+5/3:x=1/2
d,5/7:x-3=-2/7
a \(\dfrac{2}{3}x+\dfrac{1}{3}=\dfrac{1}{5}\\ \dfrac{2}{3}x=\dfrac{1}{5}-\dfrac{1}{3}\\ \dfrac{2}{3}x=\dfrac{-2}{15}\\ x=-\dfrac{2}{15}:\dfrac{2}{3}\\ x=-\dfrac{1}{5}\) b) \(\dfrac{4}{5}-\dfrac{5}{3}x=-2\\ \dfrac{5}{3}x=\dfrac{4}{5}+2\\ \dfrac{5}{3}x=\dfrac{14}{5}\\ x=\dfrac{14}{5}:\dfrac{5}{3}\\ x=\dfrac{42}{25}\)c) \(\dfrac{1}{5}+\dfrac{5}{3}:x=\dfrac{1}{2}\\ \dfrac{5}{3}:x=\dfrac{1}{2}-\dfrac{1}{5}\\ \dfrac{5}{3}:x=\dfrac{3}{10}\\ x=\dfrac{5}{3}:\dfrac{3}{10}\\ x=\dfrac{50}{9}\)d) \(\dfrac{5}{7}:x-3=-\dfrac{2}{7}\\ \dfrac{5}{7}:x=3-\dfrac{2}{7}\\ \dfrac{5}{7}:x=\dfrac{19}{7}\\ x=\dfrac{5}{7}:\dfrac{19}{7}\\ x=\dfrac{5}{19}\)