Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
\(\left|x\right|=\left|-5\right|-\left|-10\right|+15\)
\(\Rightarrow\left|x\right|=5-10+15\)
\(\Rightarrow\left|x\right|=10\)
\(\Rightarrow x=\pm10\)
\(\left|x\right|=-(-12)+(-15)+8\)
\(\Rightarrow\left|x\right|=+12+(-15)+8\)
\(\Rightarrow\left|x\right|=12+(-15)+8\)
\(\Rightarrow\left|x\right|=(-3)+8\)
\(\Rightarrow\left|x\right|=5\)
\(\Rightarrow x=\pm5\)
Bài dưới tương tự
|x|=|−5|−|−10|+15
⇒|x|=5−10+15
⇒|x|=10
⇒x=±10
|x|=−(−12)+(−15)+8
⇒|x|=+12+(−15)+8
⇒|x|=12+(−15)+8
⇒|x|=(−3)+8
⇒|x|=5
⇒x=±5
a/ x - ( 25 - x) = x - 15
=> x - 25 + x = x - 15
=> 2x - x = -15 + 25
=> x = 10
b/ x - 8 = -13 - 8
=> x = -13 - 8 + 8 = -13
c/ x - (-15) = 5 - (-19)
=> x + 15 = 5 + 19 => x = 5 + 19 - 15 = 9
d/ (x + 35) = 2x + 15 + (13 - 4)
=> x + 35 = 2x + 15 + 13 - 4
=> x - 2x = 15 + 13 - 4 - 35
=> -x = -11 => x = 11
e/ 5 - 2x = 15-(-9) - 3x
=> 5 - 2x = 15 + 9 - 3x
=> -2x + 3x = 15 + 9 - 5
=> x = 19
g/ x + 135 = 3x - 15
=> x - 3x = -15 - 135
=> -2x = -150
=> x = -150/ - 2 = 75
15 × (4 - 7) - 15 × (5 - 3)
= 15 × (-3) - 15 × 2
= 15 × (-3 - 2)
= -15 × 5
= -75
--------
73 × (8 - 59) - 59 × (8 - 73)
= 73 × 8 - 73 × 59 - 59 × 8 + 59 × 73
= 8 × (73 - 59) + 73 × (59 - 59)
= 8 × 14 + 73 × 0
= 8 × 14
= 112
15 x (4-7) - 15 x (5-3)
= 15 x (-3) - 15 x (-2)
= 15 x (-3 - (-2))
= 15 x (-1)
= -15
73 x (8-59) - 59 x (8-73)
= 73 x 8 - 59 x 73 - 59 x (-65)
= 73 x 8 - 59 x (73 - (-65))
= 73 x 8 - 59 x 8
= 8 x (73-59)
= 8 x 14
= 112
a) Ta có: \(\dfrac{-11}{15}< \dfrac{x}{15}< \dfrac{-8}{15}\)
nên -11<x<-8
hay \(x\in\left\{-10;-9\right\}\)
b) Ta có: \(\dfrac{3}{7}< \dfrac{x}{21}< \dfrac{2}{3}\)
\(\Leftrightarrow\dfrac{9}{21}< \dfrac{x}{21}< \dfrac{14}{21}\)
Suy ra: 9<x<14
hay \(x\in\left\{10;11;12;13\right\}\)
c) Ta có: \(\dfrac{-67}{21}< \dfrac{x}{168}< \dfrac{-3}{8}\)
nên \(\dfrac{-536}{168}< \dfrac{x}{168}< \dfrac{-63}{168}\)
Suy ra: -536<x<-63
hay \(x\in\left\{-535;-534;...;-64\right\}\)
Câu 30:
\(\dfrac{x+1}{8}=\dfrac{2}{x+1}\)
=>\(\left(x+1\right)^2=2\cdot8=16\)
=>\(\left[{}\begin{matrix}x+1=4\\x+1=-4\end{matrix}\right.\)
=>\(\left[{}\begin{matrix}x=3\\x=-5\end{matrix}\right.\)
=>Chọn D
Câu 31:
\(-\dfrac{7}{15}\cdot\dfrac{5}{8}\cdot\dfrac{15}{-7}\cdot\left(-16\right)\)
\(=\dfrac{5}{8}\cdot\left(-16\right)=-10\)
=>Chọn D
a)15/8+3/4-5/12
=45+18-10/24
=53/24
b)11/24.12/33+5/6
=11.12/12.2.11.3+5/6
=1/6+5/6
=6/6=1
c)15/8+7/24:5/8
=15/8+7/24.8/5
=15/8+7.8/3.8.5
=15/8+7/15
=đề sai, nếu đúng thì như này
=8/15+7/15
=15/15=1
x-15=-8-20
x-15=-28
x =-28+15
x =-13
x-15=-8-20
x-15= -28
x=-28 + 15
x = -13