1.tính
5871:[928-(247-82.5)]
2,tìm x bít
a)128-3.(x+4)=22
b)(12x-4mu3).8mu3=4.8mu4
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\(5871:\left[928-\left(247-82\cdot5\right)\right]\)
\(=5871:\left[928-\left(247-410\right)\right]\)
\(=5871:\left[928-\left(-163\right)\right]\)
\(=5871:1091\)
\(=\frac{5871}{1091}\)
b﴿ 6 chia hết cho x‐1
=> x‐1 ∈ U﴾6﴿={ ‐1;1;‐2;2;‐3;3;‐6;6}
=> x=0;2;‐1;3;‐2;4;‐5;7
b﴿ 14 chia hết cho 2x+3
=> 2x+3 ∈ U﴾14﴿={ ‐1;1;‐2;2;‐7;7;‐14;14}
Vì 2x+3 là số lẻ
=> 2x+3= ‐1;1;‐7;7
=> 2x=‐4;‐2;‐10;4
=> x= ‐2;‐1;‐5;2
a)x chia hết cho 12
x chia hết cho 25
=> x thuộc BC﴾12 , 25﴿
12 = 2^2.3 ; 25 = 5^2
=> BCNN﴾12,25﴿ = 2^2.3.5^2 = 300
B﴾300﴿ = {0;300;600;....}
Vậy x = 300
mik biết làm bài a thôi
a) 4.52-32:24
b) 5871:\(\orbr{\begin{cases}\\\end{cases}}928-\left(247-82.5\right)\)
c) 777:7+1331:113
a; 4.52 - 32 : 24
= 208 - \(\dfrac{4}{3}\)
= \(\dfrac{624}{3}\) - \(\dfrac{4}{3}\)
= \(\dfrac{620}{3}\)
c; 777 : 7 + 1331 : 113
= 111 + \(\dfrac{1331}{113}\)
= \(\dfrac{12543}{113}\) + \(\dfrac{1331}{113}\)
= \(\dfrac{13874}{113}\)
\(4^x=4^3.4^5\Rightarrow x=3+5=8\)
\(2^x=8.128\Rightarrow2^x=2^3.2^7\Rightarrow x=3+7=10\)
\(4^X=4^3.4^5\)
\(4^X\)=\(4^7\)
\(\Rightarrow\)X=7
\(2^X=8.128\)
\(2^X=2^3.2^7\)
\(2^X\)=\(2^{10}\)
\(\Rightarrow\)x=10
chú ý: dấu nhân kí hiệu là .
a. \(\Leftrightarrow16x^2+24x+9-4\left(4x^2-9\right)-5+2x=0\)
\(\Leftrightarrow16x^2+24x+9-16x^2+36-5+2x=0\)
\(\Leftrightarrow26x=-40\)
\(\Leftrightarrow x=\frac{-20}{13}\)
\(5871:\left[928-\left(247-82.5\right)\right]\)
\(=5871:\left[928-\left(247-410\right)\right]\)
\(=5871:\left[928-\left(-163\right)\right]\)
\(=5871:1091\)\(=\frac{5871}{1091}\)
\(5871:\left[928-\left(247-82.5\right)\right]\)
\(=5871:\left(928+163\right)\)
\(=5871:1091\)
\(=5,381301558\)
Chúc bạn học tốt !
\(a,128-3.\left(x+4\right)=23\\ \Rightarrow3.\left(x+4\right)=105\\ \Rightarrow x+4=35\\ \Rightarrow x=31\\ b,\left[\left(4x+28\right).3+55\right]:5=35\\ \Rightarrow\left(4x+28\right).3+55=175\\ \Rightarrow4x+28.3=120\\ \Rightarrow4x+28=60\\ \Rightarrow4x=32\\ \Rightarrow x=8.\)
c) \(\left(12x-4^3\right).8^3=4.8^4\)
\(12x-64=4.8^4:8^3\)
\(12x-64=32\)
\(12x=32+64\)
\(12x=96\)
\(x=\dfrac{96}{12}\)
\(x=8\)
d) \(720:\left[41-\left(2x-5\right)\right]:5=35\)
\(720:\left(41-2x+5\right):5=35\)
\(720:\left(46-2x\right)=35.5\)
\(720:\left(46-2x\right)=175\)
\(46-2x=720:175\)
\(46-2x=\dfrac{144}{35}\)
\(2x=46-\dfrac{144}{35}\)
\(2x=\dfrac{1466}{35}\)
\(x=\dfrac{1466}{35}:2\)
\(x=\dfrac{733}{35}\)
\(5871:\left[928-\left(247-82.5\right)\right]\)
\(=5871:\left[928-\left(247-460\right)\right]\)
\(=5871:\left[928-\left(-213\right)\right]\)
\(=5871:1141\)