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C1 lấy 2,5:100x50=1,25
C2 100;50=2 và 2,5 : 2=1,25
tik nha Nguyễn Khắc Vinh
\(a,x+3,79=15,12\)\(\Rightarrow x=15,12-3,79\)\(\Rightarrow x=11,33\)
\(b,12,1-x=5,49\)\(\Rightarrow x=12,1-5,49\Rightarrow x=6,61\)
\(c,60,45:x=1,5\)\(\Rightarrow x=60,45:1,5\Rightarrow x=40,3\)
\(d,3,5.x-1,5.x=12,5\)
\(\Rightarrow x\left(3,5-1,5\right)=12,5\)
\(\Rightarrow x.2=12,25\Rightarrow x=12,25:2=6,125\)
\(d,12,5.x-2,5.x-50=2,5.10\)
\(\Rightarrow12,5.x-2,5.x-50=25\)
\(\Rightarrow x\left(12,5-2,5\right)=25+50\)
\(\Rightarrow x.10=75\)
\(\Rightarrow x=75:10=7,5\)
a) x=11,33 b) x=6,61 c)40,3
Mình chỉ biết làm tới đó thôi. xin lỗi nha
=> 3/4.x - 1/2.x = 2,5
=> 1/4.x = 2,5
=> x = 2,5 : 1/4
=> x = 2,5 . 4
=> x = 10
dấu .=x ( nhân )
3/4x-1/2x=5/2
x.(3/4-1/2)=5/2
x.1/4=5/2
x=5/2:1/4
x=5/2.4/1
x=10/1
đúng thì tích nha
a: \(\Leftrightarrow\left(x-\dfrac{2}{5}\right):\dfrac{3}{2}=-\dfrac{5}{4}+\dfrac{5}{2}=\dfrac{5}{4}\)
\(\Leftrightarrow x-\dfrac{2}{5}=\dfrac{5}{4}\cdot\dfrac{3}{2}=\dfrac{15}{8}\)
hay x=91/40
b: \(\Leftrightarrow\left(2.5x-3.6\right)=-1\cdot\dfrac{12}{7}=\dfrac{-12}{7}\)
=>2,5x=66/35
hay x=132/175
c: \(\Leftrightarrow\left(\dfrac{15}{4}-2x\right)=\dfrac{19}{9}:\dfrac{4}{3}=\dfrac{19}{9}\cdot\dfrac{3}{4}=\dfrac{19}{12}\)
=>2x=15/4-19/12=45/12-19/12=26/12
=>x=13/12
50<x<178
x chia hết cho 2,5
=> x thuộc B(2,5) và 50<x<178
B(2,5)={0;2,5;5;7,5;10;12,5;15;17,5;....;50;52,5;55;...;162,5;165;167,5;170;172,5;175;177,5;..}
Vậy x thuộc {50;52,5;55;...;162,5;165;167,5;170;172,5;175;177,5} để 50<x<178 và chia hết cho 2,5
2x + 40%x = -2,5
=> 2x + 2/5x = -1/4
=> x(2 + 2/5) = -1/4
=> 12/5x = -1/4
=> x = -1/4 : 12/5
=> x = -5/48
\(2x-40\%x=-2,5\)
\(\Rightarrow2x-\frac{2}{5}x=-\frac{5}{2}\)
\(\Rightarrow x\left(2-\frac{2}{5}\right)=-\frac{5}{2}\)
\(\frac{\Rightarrow8}{5}x=-\frac{5}{2}\)
\(\Rightarrow x=-\frac{5}{2}:\left(-\frac{8}{5}\right)\)
\(\Rightarrow x=\frac{25}{16}\)
\(\left(x-2,5\right)^2=\frac{4}{9}\)
\(\left(x-2,5\right)^2=\left(\frac{2}{3}\right)^2\)
\(x-2,5=\frac{2}{3}\)
\(x=\frac{2}{3}+2,5\)
\(x=\frac{19}{6}\)
\(\left(2x+\frac{1}{3}\right)^3=\frac{-8}{27}\)
\(\left(2x+\frac{1}{3}\right)^3=\left(\frac{-2}{3}\right)^3\)
\(2x+\frac{1}{3}=\frac{-2}{3}\)
\(2x=\frac{-2}{3}-\frac{1}{3}\)
\(2x=-1\)
\(x=\frac{-1}{2}\)
\(\left(x-2,5\right)^2=\left(\frac{2}{3}\right)^2\)
\(\Rightarrow\)\(\orbr{\begin{cases}x-2,5=\frac{2}{3}\\x-2,5=-\frac{2}{3}\end{cases}}\)
\(\Rightarrow\)\(\orbr{\begin{cases}x=\frac{2}{3}+\frac{5}{2}\\x=-\frac{2}{3}+\frac{5}{2}\end{cases}}\)
\(\Rightarrow\)\(\orbr{\begin{cases}x=\frac{4}{6}+\frac{15}{6}=\frac{19}{6}\\x=-\frac{4}{6}+\frac{15}{6}=\frac{11}{6}\end{cases}}\)
Giải:
a) \(25\%-\dfrac{5}{4}+\dfrac{11}{6}\)
\(=\dfrac{1}{4}-\dfrac{5}{4}+\dfrac{11}{6}\)
\(=-1+\dfrac{11}{6}\)
\(=\dfrac{5}{6}\)
Vậy ...
b) \(75\%:\dfrac{11}{5}-\left(0,5\right)^2.\left(-7\right)+2,5\left(\dfrac{23}{3}-\dfrac{17}{3}\right)\)
\(=\dfrac{3}{4}:\dfrac{11}{5}-\dfrac{1}{4}.\left(-7\right)+2,5.2\)
\(=\dfrac{15}{44} +\dfrac{7}{4}+5\)
\(=\dfrac{23}{11}+5\)
\(=\dfrac{78}{11}\)
Vậy ...
c) \(45:\dfrac{18}{7}+50\%-1,25\)
\(=45:\dfrac{18}{7}+\dfrac{1}{2}-\dfrac{5}{4}\)
\(=\dfrac{35}{2}+\dfrac{1}{2}-\dfrac{5}{4}\)
\(=18-\dfrac{5}{4}\)
\(=\dfrac{67}{4}\)
Vậy ...
2x + 0,5 = -2,5
2x = -2,5 - 0,5
2x = -3
x = -3 : 2
x = - 1,5
Vậy x = 1,5
Bạn có thể đưa 50 % và -2,5 ra phân số rồi tính
2x+50%=-2,5
2x+0,5=-2,5
2x =-2,5-0,5
2x =-3
x =-3:2
x =-1,5