tim x,biet:
a,x+1/3 =3/4
b,-x-2/3=6/7
tim x biet:a)/x+1/+/3x-1/+/x-1/=3
b)/x-2/+/x-7/=4
|x+1|+|3x-1|+|x-1|=3
=} vs cả trong dấu giá trị tuyệt đối >0 thì=}
x+1+3x-1+x-1=3{=}5x=4{=}x=4/5
=}vs cả trong giá trị tuyệt đối <0 thì=}
x+1+3x-1+x-1=-3{=}5x=-4{=}x=-4/5
tim x biet:a.2x^2-1=17/8;b.(2x-0,05)(x+3)>0;c.(7-x)(x+19)>0
Cau 3 (2 diem). Tim so tu nhien x, biet:
a. 123 - x =38
b. (x+15) - 7 =33
c. 3x+3 - 13=230
`123-x=38`
`=> x= 123-38`
`=>x=85`
Vậy `x=85`
__
`(x+15) -7=33`
`=>x+15=33+7`
`=>x+16= 40`
`=>x=40-16`
`=>x=24`
Vậy `x=24`
__
`3^(x+3) -13=230`
`=> 3^(x+3) = 230+13`
`=>3^(x+3)=243`
`=> 3^(x+3)=3^5`
`=> x+3=5`
`=>x=5-3`
`=>x=2`
Vậy `x=2`
cac ban oi giup minh voi
1.tim a,b thuoc Z,biet:a.(2b-3)=-6
2.cho x,y thuoc Z thoa man x mu 2 +y mu 2 chia het cho 3.chung to x va y chia het cho 3.
tim x nguyen biet:
a 8.(x mu 2 +3).(5-x)
b)(2x + 1)mu 2=25
c) (1-3x)mu3 =64
d)(4-x)mu3 =-27
e) xmu2 -5x =0
b: \(\left(2x+1\right)^2=25\)
=>\(\left[{}\begin{matrix}2x+1=5\\2x+1=-5\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}2x=4\\2x=-6\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=2\\x=-3\end{matrix}\right.\)
c: \(\left(1-3x\right)^3=64\)
=>\(\left(1-3x\right)^3=4^3\)
=>1-3x=4
=>3x=1-4=-3
=>x=-3/3=-1
d: \(\left(4-x\right)^3=-27\)
=>\(\left(4-x\right)^3=\left(-3\right)^3\)
=>4-x=-3
=>x=4+3=7
e: \(x^2-5x=0\)
=>\(x\left(x-5\right)=0\)
=>\(\left[{}\begin{matrix}x=0\\x-5=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0\\x=5\end{matrix}\right.\)
Tim x biet:A. 2/3+x=-45%
B:x/5=5/6+-19/30.ai nhanh tay giai gium cho minh thi minh tick cho!
tim x,biet:a,x2+3x+1⋮ x-1
b,18x+⋮7
c,4x-5⋮13
a: \(\Leftrightarrow x^2-x+4x-4+5⋮x-1\)
\(\Leftrightarrow x-1\in\left\{1;-1;5;-5\right\}\)
hay \(x\in\left\{2;0;6;-4\right\}\)
c: \(\Leftrightarrow4x-5=13k\left(k\in Z\right)\)
=>4k=13k+5
hay \(x=\dfrac{13k+5}{4}\)
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: \(4x-\left(x+\dfrac{1}{2}\right)=2x-\left(\dfrac{1}{2}-5\right)\)
\(\Leftrightarrow3x-\dfrac{1}{2}-2x+\dfrac{1}{2}-5=0\)
\(\Leftrightarrow x=5\)
tim so nguyen x biet:a,(x2+8).(x2-9) = 0 b, (x2-5).(x2-25)<0 c,(x-3).(x+7)<0
tìm x, biết
a) x = 1 phần 2 + 3 phần 4
b) x phần 5 = 5 phần 6 - 19 phần 30
c) x = 1 phần 2 - 2 phần 3
d) x phần 3 = 2 phần 3 trừ 1 phần 7
a) \(x=\dfrac{1}{2}+\dfrac{3}{4}\)
\(\Rightarrow x=\dfrac{2}{4}+\dfrac{3}{4}\\ \Rightarrow x=\dfrac{5}{4}\)
b) \(\dfrac{x}{5}=\dfrac{1}{2}-\dfrac{2}{3}\)
\(\Rightarrow\dfrac{x}{5}=\dfrac{3}{6}-\dfrac{4}{6}\)
\(\Rightarrow\dfrac{x}{5}=-\dfrac{1}{6}\)
\(\Rightarrow x=-\dfrac{1}{6}.5\)
\(\Rightarrow x=-\dfrac{5}{6}\)
c) \(x=\dfrac{1}{2}-\dfrac{2}{3}\)
\(\Rightarrow x=\dfrac{3}{6}-\dfrac{4}{6}\)
\(\Rightarrow x=-\dfrac{1}{6}\)
d) \(\dfrac{x}{3}=\dfrac{2}{3}-\dfrac{1}{7}\)
\(\Rightarrow\dfrac{x}{3}=\dfrac{14}{21}-\dfrac{3}{21}\)
\(\Rightarrow\dfrac{x}{3}=\dfrac{11}{21}\)
\(\Rightarrow x=\dfrac{11}{21}.3\)
\(\Rightarrow x=\dfrac{33}{21}\)