Tìm x biết : -5./x+1/-3/x+3/=-16
Tìm x, biết: a) x = 1/4 + 5/13 b) x/3 = 2/3 + -1/7 c) x/3 = 16/24 + 24/ 36
d) x/15 = 1/5 + 2/3
\(a)x=\dfrac{1}{4}+\dfrac{5}{13}=\dfrac{33}{52}.\\ b)\dfrac{x}{3}=\dfrac{2}{3}+\dfrac{-1}{7}.\\ \Leftrightarrow\dfrac{x}{3}=\dfrac{11}{21}.\\ \Leftrightarrow\dfrac{7x}{21}=\dfrac{11}{21}.\\ \Rightarrow7x=11.\\ \Leftrightarrow x=\dfrac{11}{7}.\\ c)\dfrac{x}{3}=\dfrac{16}{24}+\dfrac{24}{36}=\dfrac{2}{3}+\dfrac{2}{3}=\dfrac{4}{3}.\\ \Rightarrow x=4.\\ d)\dfrac{x}{15}=\dfrac{1}{5}+\dfrac{2}{3}=\dfrac{13}{15}.\\ \Rightarrow x=13.\)
Tìm x biết: a) x . \(\dfrac{-3}{4}\) = \(\dfrac{2}{5}\) + \(\dfrac{3}{4}\) b) 1 - 1\(\dfrac{1}{5}\)x = 60%
c) \(\dfrac{1}{2}\)x + \(\dfrac{3}{2}\)x + x = 16
Tìm x biết:
a,(2/3)^x+1=16^81
b,(x+2/5)^5=(x+2/5)^3
a, xem lại đề , sửa rồi thì báo cho tui
b, \(\left(x+\frac{2}{5}\right)^5=\left(x+\frac{2}{5}\right)^3\)
\(\Rightarrow\left(x+\frac{2}{5}\right)^5-\left(x+\frac{2}{5}\right)^3=0\)
\(\Rightarrow\left(x+\frac{2}{5}\right)^3.\left[\left(x+\frac{2}{5}\right)^2-1\right]=0\)
\(\Rightarrow\hept{\begin{cases}\left(x+\frac{2}{5}\right)^3=0\\\left(x+\frac{2}{5}\right)^2-1=0\end{cases}\Rightarrow\hept{\begin{cases}x=-\frac{2}{5}\\\left(x+\frac{2}{5}\right)^2=1\end{cases}}}\)
Ta có \(\left(x+\frac{2}{5}\right)^2=1\)
\(\Rightarrow\hept{\begin{cases}x+\frac{2}{5}=1\\x+\frac{2}{5}=-1\end{cases}\Rightarrow\hept{\begin{cases}x=\frac{3}{5}\\x=-\frac{7}{5}\end{cases}}}\)
Vậy \(x\in\text{{}-\frac{2}{5};\frac{3}{5};-\frac{7}{5} \)}
Tìm x, biết:
a) (x - 3) + (x - 2) + (x -1) + ... + 15 + 16 = 16
b) (x - 5) + (x - 4) + (x - 3) + ... + 13 + 14 = 14
Tìm x biết :
a. 5(2x + 1) - 2x - 1 = 16
b. 4x(x + 5) = 3(x + 5)
c. x(x - 2) = 3 - 6
a, \(5\left(2x+1\right)-2x-1=16\)
\(\Leftrightarrow10x+5-2x-1-16=0\Leftrightarrow8x-12=0\Leftrightarrow x=\frac{3}{2}\)
b, \(4x\left(x+5\right)=3\left(x+5\right)\Leftrightarrow4x\left(x+5\right)-3\left(x+5\right)=0\)
\(\Leftrightarrow\left(4x-3\right)\left(x+5\right)=0\Leftrightarrow x=\frac{3}{4};-5\)
c, \(x\left(x-2\right)=3-6\Leftrightarrow x^2-2x+3=0\)
vô nghiệm
a) 5(2x+1)-2x-1=16
10x + 5 -2x =17
8x = 12
x= 3/2
b) 4x(x+5) = 3(x+5)
4x2+20x=3x+15
4x2-17x-15=0
x=5; x=-3/4
Tìm x biết:
1-(\(5\dfrac{3}{8}\)+x\(-7\dfrac{5}{24}\)):(\(-16\dfrac{2}{3}\))=0
`1-(5 3/8+x-7 5/24):(-16 2/3)=0`
`=>1-(5+3/8+x-7-5/24):(-50/3)=0`
`=>1=(x-2-11/6):(-50/3)`
`=>1=(x-11/6):(-50/3)`
`=>x-11/6=-50/3`
`=>x=-89/6`
Vậy `x=-89/6`
\(1-\left(5\dfrac{3}{8}+x-7\dfrac{5}{24}\right):\left(-16\dfrac{2}{3}\right)=0\)
\(\Leftrightarrow1-\left(\dfrac{43}{8}+x-\dfrac{173}{24}\right):\dfrac{50}{3}=0\)
\(\Leftrightarrow1-\left(\dfrac{129}{24}-\dfrac{173}{24}+x\right).\dfrac{3}{50}=0\)
\(\Leftrightarrow1+\dfrac{11}{6}-x.\dfrac{3}{50}=0\)
\(\Leftrightarrow\dfrac{17}{6}-x.\dfrac{3}{50}=0\)
\(\Leftrightarrow x.\dfrac{3}{50}=\dfrac{17}{6}\)
\(\Leftrightarrow x=\dfrac{425}{9}\)
-Chúc bạn học tốt-
\(1-\left(5\dfrac{3}{8}+x-7\dfrac{5}{24}\right):\left(-16\dfrac{2}{3}\right)=0\)
\(1-\left(\dfrac{43}{8}:\dfrac{-50}{3}+x:\dfrac{-50}{3}-\dfrac{173}{24}:\dfrac{-50}{3}\right)=0\)
\(1-\dfrac{-129}{400}-x:\dfrac{-50}{3}+\dfrac{-173}{400}=0\)
\(\left(1+\dfrac{129}{400}+\dfrac{-173}{400}\right)-x:\dfrac{-50}{3}=0\)
\(\dfrac{89}{100}-x:\dfrac{-50}{3}=0\)
\(x:\dfrac{-50}{3}=\dfrac{89}{100}-0\)
\(x:\dfrac{-50}{3}=\dfrac{89}{100}\)
\(x=\dfrac{89}{100}.\dfrac{-50}{3}\)
\(x=\dfrac{-89}{6}\)
Bài 3. Tìm x biết:
1) |x| = 10 2) |x - 8| = 0 3) 7 + |x| = 12
4) |x + 1| = 3 5) 15 - x = 16 - (14 - 42) 6) 210 - (x - 12) = 168
1/ `|x|=10<=> x=\pm 10`
2/ `|x-8|=0<=>x-8=0<=>x=8`
3/ `7+|x|=12<=>|x|=5<=>x=\pm 5`
4/ `|x+1|=3`
$\Leftrightarrow\left[\begin{array}{1}x+1=3\\x+1=-3\end{array}\right.\\\Leftrightarrow\left[\begin{array}{1}x=3\\x=-4\end{array}\right.$
5/ `15-x=16-(14-42)`
`<=>15-x=16+28`
`<=>15-x=44`
`<=>x=-29`
6/ `210-(x-12)=168`
`<=>210-x+12=168`
`<=>222-x=168`
`<=>x=54`
1.
\(\left|x\right|=10\Leftrightarrow x=\pm10\)
2.
\(\left|x-8\right|=0\Leftrightarrow x-8=0\Leftrightarrow x=8\)
3.
\(7+\left|x\right|=12\Leftrightarrow\left|x\right|=5\Leftrightarrow x=\pm5\)
Tìm x biết:
a) x^2-7x(x-4)=16
b) (x+5)^2-3(x+1)=22
a: \(\Leftrightarrow x^2-7x^2+28x=16\)
\(\Leftrightarrow-6x^2+28x-16=0\)
\(\Leftrightarrow3x^2-14x+8=0\)
\(\text{Δ}=\left(-14\right)^2-4\cdot3\cdot8=100\)
Vì Δ>0 nên phương trình có hai nghiệm phân biệt là:
\(\left\{{}\begin{matrix}x_1=\dfrac{14-10}{6}=\dfrac{4}{6}=\dfrac{2}{3}\\x_2=\dfrac{14+10}{6}=\dfrac{24}{6}=4\end{matrix}\right.\)
a) x2-7x(x-4)=16
x2-16-7x(x-4)=0
(x-4)(x+4)-7x(x-4)=0
(x-4)(x+4-7x)=0
(x-4)(-6x+4)=0
=>x=4 hoặc x=2/3
b) (x+5)^2-3(x+1)=22
x2+10x+25-3x-3=22
x2+10x-3x=22+3-25
x2+7x=0
x(x+7)=0
=>x=0 hoặc x=-7
Câu 4: Tìm x biết :
a, x-\(\dfrac{5}{6}\)=\(\dfrac{1}{2}\) b,3\(\dfrac{1}{3}\)x+16\(\dfrac{3}{4}\)= -13,25
a) \(x-\dfrac{5}{6}=\dfrac{1}{2}\)
\(x=\dfrac{1}{2}+\dfrac{5}{6}\)
\(x=\dfrac{4}{3}\)
vậy x = ....
b) \(3\dfrac{1}{3}x+16\dfrac{3}{4}=-13,25\)
\(\dfrac{10}{3}\)\(x+\dfrac{67}{4}=-13,25\)
\(\dfrac{10}{3}x=\left(-13,25\right)-\dfrac{67}{4}\)
\(\dfrac{10}{3}x=-30\)
\(x=\left(-30\right):\dfrac{10}{3}\)
\(x=-9\)
vậy x =...
sai mog bn thông cảm!!!