Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
b: \(\dfrac{5}{7}-\dfrac{2}{3}\cdot x=\dfrac{4}{5}\)
=>\(\dfrac{2}{3}x=\dfrac{5}{7}-\dfrac{4}{5}=\dfrac{25-28}{35}=\dfrac{-3}{35}\)
=>\(x=-\dfrac{3}{35}:\dfrac{2}{3}=\dfrac{-3}{35}\cdot\dfrac{3}{2}=-\dfrac{9}{70}\)
c: \(\dfrac{1}{2}x+\dfrac{3}{5}x=-\dfrac{2}{3}\)
=>\(x\left(\dfrac{1}{2}+\dfrac{3}{5}\right)=-\dfrac{2}{3}\)
=>\(x\cdot\dfrac{5+6}{10}=\dfrac{-2}{3}\)
=>\(x\cdot\dfrac{11}{10}=-\dfrac{2}{3}\)
=>\(x=-\dfrac{2}{3}:\dfrac{11}{10}=-\dfrac{2}{3}\cdot\dfrac{10}{11}=\dfrac{-20}{33}\)
d: \(\dfrac{4}{7}\cdot x-x=-\dfrac{9}{14}\)
=>\(\dfrac{-3}{7}\cdot x=\dfrac{-9}{14}\)
=>\(\dfrac{3}{7}\cdot x=\dfrac{9}{14}\)
=>\(x=\dfrac{9}{14}:\dfrac{3}{7}=\dfrac{9}{14}\cdot\dfrac{7}{3}=\dfrac{3}{2}\)
1) \(\left|4-2x\right|.\dfrac{1}{3}=\dfrac{1}{3}\)
\(\left|4-2x\right|=\dfrac{1}{3}:\dfrac{1}{3}\)
\(\left|4-2x\right|=\dfrac{1}{3}.3\)
\(\left|4-2x\right|=1\)
=>\(4-2x=\pm1\)
+)\(TH1:4-2x=1\) +)\(TH2:4-2x=-1\)
\(2x=4-1\) \(2x=4-\left(-1\right)\)
\(2x=3\) \(2x=4+1\)
\(x=3:2\) \(2x=5\)
\(x=1,5\) \(x=5:2\)
Vậy x=1,5 \(x=2,5\)
Vậy x=2,5
2) \(\left(-3\right)^2:\left|x+\left(-1\right)\right|=-3\)
\(9:\left|x+\left(-1\right)\right|=-3\)
\(\left|x+\left(-1\right)\right|=9:\left(-3\right)\)
\(\left|x+\left(-1\right)\right|=-3\)
=> \(x+\left(-1\right)\) sẽ không có giá trị nào ( Vì giá trị tuyệt đối luôn luôn lớn hơn hoặc bằng 0 )
Vậy x = \(\varnothing\)
nhiều quá :((
\(a,2\left(x-5\right)-3\left(x+7\right)=14\)
\(2x-10-3x-21=14\)
\(-x-31=14\)
\(-x=45\)
\(x=45\)
\(b,5\left(x-6\right)-2\left(x+3\right)=12\)
\(5x-30-2x-6=12\)
\(3x-36==12\)
\(3x=48\)
\(x=16\)
\(c,3\left(x-4\right)-\left(8-x\right)=12\)
\(3x-12-8+x=0\)
\(4x-20=0\)
\(4x=20\)
\(x=5\)
Cố nốt nha bn !
cảm ơn, bn nha:)))
mà hình như bạn TOP 3 trả lời câu hỏi pải ko nhỉ???
1) 2(3x+5)-6=9
2(3x+5) =9+6
2(3x+5) =15
3x+5 = 15:2
3x+5 = \(\frac{15}{2}\)
3x = \(\frac{15}{2}-5\)
3x =\(\frac{5}{2}\)
x = \(\frac{5}{2}:3\)
x = \(\frac{5}{6}\)
2) 5x+3(4+2x)=25
5x+12+6x=25
5x+6x =-12+25
11x =13
x =13:11
x =\(\frac{13}{11}\)
3) 3(4x+1)+2(x-1)=105
12x+3+2x-2=105
12x+2x = -3+2+105
14x =104
x = 104:14
x = \(\frac{52}{7}\)
4) \(30-[2\left(x-3\right)-2]=14\)
\(2\left(x-3\right)-2\)=\(30-14\)
\(2\left(x-3\right)-2=16\)
\(2\left(x-3\right)=16+2\)
\(2\left(x-3\right)=18\)
\(x-3=18:2\)
\(x-3=9\)
\(x=9+3\)
\(x=12\)
k mình nha !!!!!!
1: Ta có: \(20-2\left(x+4\right)=4\)
\(\Leftrightarrow2\left(x+4\right)=16\)
\(\Leftrightarrow x+4=8\)
hay x=4
5: Ta có: \(\left(x+1\right)^3=27\)
\(\Leftrightarrow x+1=3\)
hay x=2
a) x+30%x=-1.31
=> 100%x+30%x=-1.31
=>x.(100%+30%)=-1.31
=>x.13/10=-1.31=-1.31:13/10=-131/130
b) (x-1/2):1/3+5/7=9+5/7
=>(x-1/2).3+5/7=68/7
=>(x-1/2).3=68/7-5/7=9
=>x-1/2=9:3=3
=>x=3+1/2=3 1/2( hỗn số)
c) 1/2x-3/4=14/9.3/7
=>1/2x-3/4=2/3
=>1/2x=2/3+3/4=17/12
x=17/12:1/2=17/12.2=17/6
d) - 5/6 -x = 7/12+ -1/3
=>- 5/6 -x = 7/12+ -4/12=1/4
=> x = -5/6 -1/4=-13/12
e) x + 3/-15 = 1/3
=> x= 1/3 - -3/15 =1/3+3/15
=> x=5/15 + 3/15=8/15
f) (4,5 -2 x). (-1 4/7)=11/14
=> 4,5 -2x=11/14 : -3/7=11/14. -7/3=-11/6
=>-2x=-11/6-9/2= -11/6 -27/6 =-19/3
=>x= -19/3: -2x=19/6
Chúc bn thi HKII tốt!!!