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1.Xx3,7+Xx6,3=120
Xx(3,7+6,3)=120
Xx10=120
X=120:10
X=12
2.128xX-12xX-16xX=5208000
(128-12-16)xX=5208000
100xX=5208000
X=5208000:100
X=52080
3.5xX+3,75xX+125xX=20
(5+3,75+125)xX=20
128,8xX=20
X=128,8:20
X=6,44
Câu cuối cùng cậu ghi sai rồi! 3,75xX+125xX nhé
a)13x3x32,27+67,63x39
=39x32,27+67,63x39
=39x(32,27+67,63)
=39x100
=3900
b,= 1- [ 1/2 x 1/3 x1/4 x..... x 1/100 ]
=1/2 x 2/3 x 3/4 x .......x 99/100
= 1x2x3x......x99 / 2x3x4x...... x100 [ rút gọn ]
= 1/100
Gợi ý: Các biểu thức mũ chẵn đều không âm.
\(a^{2n}+b^{2n}\le0\Leftrightarrow a^{2n}+b^{2n}=0\Leftrightarrow a=b=0\)
a,\(\left(x-\frac{2}{5}\right)^{2010}+\left(y+\frac{3}{7}\right)^{468}\)< \(0\)
Vì \(\left(x-\frac{2}{5}\right)^{2010}\);\(\left(y+\frac{3}{7}\right)^{468}\)đều > \(0\)
=> \(\left(x-\frac{2}{5}\right)^{2010}=0\)
\(\left(y+\frac{3}{7}\right)^{468}=0\)
=> \(\left(x-\frac{2}{5}\right)^{2010}=0^{2010}\)
\(\left(y+\frac{3}{7}\right)^{468}=0^{468}\)
=> \(x-\frac{2}{5}=0\)
\(y-\frac{3}{7}=0\)
=> \(x=\frac{2}{5}\)
\(y=\frac{3}{7}\)
Vậy \(x=\frac{2}{5}\)\(y=\frac{3}{7}\)
\(a,\left(16.23+16.77\right)-\left(5.30-5.20\right)\)
\(=16.\left(23+77\right)-5.\left(30-20\right)\)
\(=16.100-5.10\)
\(=1600-50\)
\(=1550\)
\(b,8\frac{1}{2}\div\frac{17}{5}+\frac{6}{8}\div3\frac{2}{3}\)
\(=\frac{17}{2}.\frac{5}{17}+\frac{3}{4}\div\frac{11}{3}\)
\(=\frac{17}{2}.\frac{5}{17}+\frac{3}{4}.\frac{3}{11}\)
\(=\frac{5}{2}+\frac{9}{44}\)
\(=\frac{110}{44}+\frac{9}{44}\)
\(=\frac{119}{44}\)
\(a,=16.100-5.10=1600-50=1550\)
\(b,8\frac{1}{2}:\frac{17}{5}+\frac{6}{8}:3\frac{2}{3}=\frac{17}{2}.\frac{5}{17}+\frac{6}{8}:\frac{11}{3}=\frac{5}{2}+\frac{18}{88}=\frac{220}{88}+\frac{18}{88}=\frac{238}{88}=2\frac{31}{44}\)
\(\left(x+\frac{1}{2}\right)+\left(x+\frac{1}{4}\right)+\left(x+\frac{1}{8}\right)+\left(x+\frac{1}{16}\right)=1\)
\(\Rightarrow\left(x+x+x+x\right)+\left(\frac{1}{2}+\frac{1}{4}+\frac{1}{8}+\frac{1}{16}\right)=1\)
\(\Rightarrow4x+\frac{15}{16}=1\)
\(\Rightarrow4x=\frac{1}{16}\)
\(\Rightarrow x=\frac{1}{64}\)
x:6=24+6
x:6=30
x=30 x 6
x=180
23+x:2=37
x:2=37-23
x:2=14
x=14 x 2
x=28
214-136:x=197
136:x=214-197
136:x=17
x=136:17
x=8
(x-4):6:5=10
(x-4):6=10 x 5=50
(x-4)=50 x 6
x-4=300
x=300+4=304
(x+1)+(x+2)+...+(x+10)=755
10x + (1+2+...+10)=755
10x + (1+10) x [(10-1):1+1]:2=755
10x + 55 = 755
10x=755-55
10x=700
x=700:10=70
chúc bạn học tốt nha
\(\left(a\right)\frac{34-x}{30}=\frac{5}{6}\)
\(\frac{34-x}{30}=\frac{25}{30}\)
34 - x = 25
x = 34 - 25 = 9
\(\left(b\right)\frac{x+13}{34}=\frac{12}{17}\)
\(\frac{x+13}{34}=\frac{24}{34}\)
x + 13 = 24
x = 24 - 13 = 11
\(\left(c\right)\left(x+\frac{1}{3}\right)+\left(x+\frac{1}{9}\right)+\left(x+\frac{1}{27}\right)+\left(x+\frac{1}{81}\right)=\frac{56}{81}\)
\(4x+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}=\frac{56}{81}\)
Đặt \(A=\frac{1}{3}+\frac{1}{9}+\frac{1}{27}+\frac{1}{81}\)
Ta có : \(3A=1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}\)
\(3A-A=1+\frac{1}{3}+\frac{1}{9}+\frac{1}{27}-\frac{1}{3}-\frac{1}{9}-\frac{1}{27}-\frac{1}{81}\)
\(2A=1-\frac{1}{81}=\frac{80}{81}\)
\(A=\frac{80}{81}\div2=\frac{40}{81}\)
\(\Rightarrow4x+\frac{40}{81}=\frac{56}{81}\)
\(4x=\frac{56}{81}-\frac{40}{81}\)
\(4x=\frac{16}{81}\)
\(x=\frac{16}{81}\div4=\frac{4}{81}\)
a)435-(x+16)=425:17 b)128.x-12.x-16x=5208000
=>435-(x+16)=25 =>x.(128-12-16)=5208000
=>x+16=435-25=410 =>x.100=5208000
x=410-16=394 =>x=52080
Vậy ...... Vậy............