Tìm x:
4 + 8 + 12 + ... + 4 * x = 180
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4+8+12+...+4.x=180
\(4+8+12+...+4x=180\)
\(\Rightarrow4.\left(1+2+3+...+x\right)=180\)
\(\Rightarrow1+2+3+...+x=180:4=45\)
\(\Rightarrow x=\left(x+1\right).x:2=45\)
\(\Rightarrow\left(x+1\right).x=45.2=90\Rightarrow90=9.10\)
\(\Rightarrow x=9\)
1: \(\Leftrightarrow x=UCLN\left(24;36;150\right)=6\)
2: \(\Leftrightarrow x\in\left\{24;48;72;...\right\}\)
mà 16<=x<=50
nên \(x\in\left\{24;48\right\}\)
3: \(\Leftrightarrow x\inƯ\left(6\right)\)
mà x>-10
nên \(x\in\left\{1;-1;2;-2;3;-3;6;-6\right\}\)
4: \(\Leftrightarrow x\in BC\left(4;5;8\right)\)
\(\Leftrightarrow x\in\left\{...;-40;0;40;80;120;160;200;...\right\}\)
mà -20<x<180
nên \(x\in\left\{0;40;80;120;160\right\}\)
\(x\) ⋮ 5; \(x\) ⋮ 4; \(x⋮\) 8; - 20 < \(x\) < 180
⇒ \(x\) BC(4; 5; 8)
4 = 22; 5 = 5; 8 = 23; BCNN(4;5;8) = 23.5 = 40
⇒ \(x\) \(\in\) {0; 40; 80; 120; 160; 200; ...;}
Vì -20 < \(x\) < 180 nên \(x\) \(\in\) {0; 40; 80; 120; 160; 200}
\(\frac{12}{26}=\frac{-x}{4}=\frac{21}{y}=\frac{z}{180}\)
\(\Rightarrow\frac{12}{26}=\frac{-x}{4}\Leftrightarrow-x.26=48\Leftrightarrow x=\frac{-24}{13}\)
\(\Rightarrow\frac{12}{26}=\frac{21}{y}\Leftrightarrow12.y=546\Leftrightarrow y=\frac{91}{2}\)
\(\Rightarrow\frac{12}{26}=\frac{z}{180}\Leftrightarrow z.26=2160\Leftrightarrow z=\frac{1080}{13}\)
Vậy : ...
chúc bạn học tốt
a 180 -(x + 15) : 4 =80:5 180 - (x + 15) : 4 = 16 180 - ( x + 15) = 16 x 4 180 - ( x + 15 ) = 64 x + 15 = 180 - 64 x + 15 = 116 x= 116 - 15 x = 101
98775 - 32 x 85
=98775 -2720
=96055
67500 - 24 x 236
= 67500 -5664
=61836
568 + 101598 : 287
= 568 +354
=922
6875 + 980 -180
=7855 -180
=7675
\(\dfrac{2}{5}+\dfrac{3}{10}-\dfrac{1}{2}\)
\(=\dfrac{7}{10}-\dfrac{1}{2}\)
= \(\dfrac{1}{5}\)
\(\dfrac{8}{11}+\dfrac{8}{33}x\dfrac{3}{4}\)
\(=\dfrac{8}{11}+\dfrac{2}{11}\)
\(=\dfrac{10}{11}\)
\(\dfrac{7}{9}x\dfrac{3}{14}:\dfrac{5}{8}\)
\(=\dfrac{1}{6}:\dfrac{5}{8}\)
\(=\dfrac{1}{6}x\dfrac{8}{5}\)
\(=\dfrac{8}{30}\)
\(=\dfrac{4}{15}\)
\(\dfrac{5}{12}-\dfrac{7}{32}:\dfrac{21}{16}\)
\(=\dfrac{5}{12}-\dfrac{7}{32}x\dfrac{16}{21}\)
\(=\dfrac{5}{12}-\dfrac{1}{6}\)
\(=\dfrac{5}{12}-\dfrac{2}{12}\)
\(=\dfrac{3}{12}=\dfrac{1}{4}\)
d, X/8*32+X/3*18-X/5*10=120
X*32/8+X*18/3-X*10/5=120
32X/8+18X/3-10X/5=120
4X+6X-2X=120
8X=120
X=120/8
X=15
a) x : 4 = 8
x = 8 × 4
x = 32
b) 4 × x = 12 + 8
4 × x = 20
x = 20 : 4
x = 5
c) 30 : x = 14 + 16
30 : x = 30
x = 30 : 30
x = 1
4 + 8 + 12 + ... + 4 * x = 180
=> 4. ( 1 + 2 + 3 + ... + x) = 180
=> 1 + 2 + 3 + ... + x = 180 : 4
=> 1 + 2 + 3 + ... + x = 45
=> x * ( x + 1 ) : 2 = 45
=> x * ( x + 1 ) = 45 * 2 = 90
=> x * ( x + 1 ) = 9 * 10
=> x = 9.
Nếu thấy đúng cho mình xin nha