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\(a,\left(x+3\right)\left(5-x\right)=0\\ \Rightarrow\left\{{}\begin{matrix}x+3=0\\5-x=0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=-3\\x=5\end{matrix}\right.\)
\(c,x+17⋮x+3\\ x+3+14⋮x+3\\ 14⋮x+3\\ x+3\inƯ\left(14\right)=\left\{\pm14;\pm7\pm2;\pm1\right\}\)
Từ đó bạn tìm những giá trị của x nha!
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a)56-(x+5):2=40
(x+5):2=56-40
(x+5):2=16
x+5=16:2
x+5=8
x=8-5
x=3
Vậy x=3
b)|x+2|=33
|x+2|=27
\(\Rightarrow\orbr{\begin{cases}x+2=27\\x+2=-27\end{cases}}\)
\(\Rightarrow\orbr{\begin{cases}x=27-2=25\\x=-27-2=-29\end{cases}}\)
Vậy x = 25 hoặc x = -29
\(a,56-\left(x+5\right):2=40\)
\(56-\left(x+5\right)=80\)
\(x+5=-24\Leftrightarrow x=-29\)
\(b,|x+2|=3^3\)
\(|x+2|=27\)
\(Th1:x+2=27\Leftrightarrow x=25\)
\(Th2:x+2=-27\Leftrightarrow x=-29\)
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a)26 + 5x = 3x + 56
5x – 3x = 56 – 26
2x = 30
x = 30 : 2 = 15
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Bài 1:
a) \(\frac{16}{15}.\frac{\left(-5\right)}{14}.\frac{54}{24}.\frac{56}{21}\)
\(=\frac{4.2.2}{5.3}.\frac{\left(-5\right)}{2.7}.\frac{3.3}{4}.\frac{8}{3}\)
\(=\frac{4.2.2.\left(-5\right).3.3.8}{5.3.2.7.4.3}\)
\(=\frac{-16}{7}\)
b) \(\frac{7}{3}.\frac{\left(-5\right)}{2}.\frac{15}{21}.\frac{4}{\left(-5\right)}\)
\(=\frac{7}{3}.\frac{\left(-5\right)}{2}.\frac{5}{7}.\frac{2.2}{\left(-5\right)}\)
\(=\frac{7.\left(-5\right).5.2.2}{3.2.7.\left(-5\right)}\)
\(=\frac{10}{3}\)
Bài 2:
a) \(\frac{21}{24}.\frac{11}{9}.\frac{5}{7}=\frac{7}{8}.\frac{11}{9}.\frac{5}{7}=\frac{11.5}{8.9}=\frac{55}{72}\)
b) \(\frac{5}{23}.\frac{17}{26}+\frac{5}{23}.\frac{9}{26}\)
\(=\frac{5}{23}.\left(\frac{17}{26}+\frac{9}{26}\right)=\frac{5}{23}.1=\frac{5}{23}\)
c) \(\left(\frac{3}{29}-\frac{1}{5}\right).\frac{29}{3}=\frac{3}{29}.\frac{29}{3}-\frac{1}{5}.\frac{29}{3}\)
\(=1-1\frac{14}{15}=\frac{14}{15}\)
Bài 3:
a) x/5 = 2/5
=> x =2
b) -4/x = 20/14 = 10/7
=> -4/x = 10/7
=> x.10 = (-4).7
x.10 = - 28
x= -28 :10
x= -2,8
c) 4/7 = 12/x = 12/ 21
=> 12/x = 12/21
=> x = 21
d) 3/7 = x / 21 = 9/21
=> x/21 = 9/21
=> x= 9
26 + 5 x = 3 x + 56 => 5x - 3x = 56 - 26 . suy ra : 2x = 30 . x = 30 : 2 = 15
=> 5x - 3x = 56 - 26
=> 2x = 30
=> x = 30 : 2
=> x = 15