Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
a) <=> 15-5x-20=-12-3
<=> -5x=-12-3-15+20=-10
=>x=-10:(-5)=2
b)<=>7-x-25-7=-25
<=> -x=-25-7+25+7=0 =>x=0
c) /x+2/=0 => x+2=0 =>x=-2
d) sai đề
e)<=> /x-5/ = 7
<=> \(\orbr{\begin{cases}x-5=7\\x-5=-7\end{cases}}\)
<=> \(\orbr{\begin{cases}x=12\\x=-2\end{cases}}\)
g) <=> -x-20-8+2x=-15
<=> x=-15+20+8=13
1) \(...\Rightarrow x-7=0\Rightarrow x=7\)
2) \(...\Rightarrow x-4=0\Rightarrow x=4\)
3) \(...\Rightarrow6x-12=0\Rightarrow6x=12\Rightarrow x=12:6=2\)
4) \(...\Rightarrow9x-27=0\Rightarrow9x=27\Rightarrow x=27:9=3\)
5) \(...\Rightarrow15-x=30-25\Rightarrow15-x=5\Rightarrow x=15-5=10\)
6) \(...\Rightarrow43-24+x=20\Rightarrow19+x=20\Rightarrow x=20-19=1\)
7) \(...\Rightarrow2x+14-17=25\Rightarrow2x-3=25\Rightarrow2x=28\Rightarrow x=28:2=14\)
8) \(...\Rightarrow3x+21-15=27\Rightarrow3x-6=27\Rightarrow3x=33\Rightarrow x=33:3=11\)
9) \(...\Rightarrow15+4x-8=95\Rightarrow4x+7=95\Rightarrow4x=88\Rightarrow x=88:4=22\)
10) \(...\Rightarrow20-x-14=5\Rightarrow6-x=5\Rightarrow x=6-5=1\)
11) \(...\Rightarrow24+15-3x=27\Rightarrow39-3x=27\Rightarrow3x=39-27\Rightarrow3x=12\Rightarrow x=12:3=4\)
a) 25. (x-4) = 0
=> x -4 =0
x = 4
b) 43 - (24-x) = 20
43 - 24 + x = 20
19 + x = 20
x = 1
c) 3.(x+7) - 15 = 27
3.x + 21 - 15 = 27
3.x + 6 = 27
3.x = 21
x = 7
d)... bn ghi thiếu đề r
e) (2.x-6).(x-7) = 0
=> 2.x -6 = 0 => 2x = 6 => x = 3
x - 7 = 0 => x = 7
KL: x = 3 hoặc x = 7
phần d lm tương tự như phần f nha bn!
a,25(x-4)=0
x-4=0
x=4
b,43-(24-x)=20
43-24+x=20
x=1
c,3(x+7)-15=27
3x+21-15=27
3x=21
x=7
d,(x-4)(x-12)=0
x-4=0=>x=4
x-12=0=>x=12
e,(2x-6)(x-7)=0
2x-6=0=>x=3
x-7=0=>x=7
f,(5x-10)(2x-8)=0
5x-10=0=>x=2
2x-8=0=>x=2
a) \(5\left(x-7\right)=0\)
\(\Rightarrow x-7=0\)
\(\Rightarrow x=7\)
b) \(25\left(x-4\right)=0\)
\(\Rightarrow x-4=0\)
\(\Rightarrow x=4\)
c) \(\left(34-2x\right)\left(2x-6\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}34-2x=0\\2x-6=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}2x=34\\2x=6\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=17\\x=3\end{matrix}\right.\)
d) \(\left(2019-x\right)\left(3x-12\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}2019-x=0\\3x-12=0\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2019\\3x=12\end{matrix}\right.\)
\(\Rightarrow\left[{}\begin{matrix}x=2019\\x=\dfrac{12}{3}=4\end{matrix}\right.\)
e) \(57\left(9x-27\right)=0\)
\(\Rightarrow9x-27=0\)
\(\Rightarrow9\left(x-3\right)=0\)
\(\Rightarrow x-3=0\)
\(\Rightarrow x=3\)
a) 5.(x-7)=0⇔x-7=0⇔x=7
b) 25(x-4)=0⇔x-4=0⇔x=4
c) (34-2x).(2x-6)=0
⇔ 34-2x=0 hoặc 2x-6=0
⇔2x=34 hoặc 2x=6
⇔ x=17 hoặc x=3
d) (2019-x).(3x-12)=0
⇔ 2019-x=0 hoặc 3x-12=0
⇔ x=2019 hoặc x=4
e) 57.(9x-27)=0
⇔ 9x-27=0
⇔ x=3
f) 25+(15-x)=30
⇔ 15-x=5
⇔ x=10
g) 43-(24-x)=20
⇔ 24-x=23
⇔ x=1
h) 2.(x-5)-17=25
⇔ 2(x-5)=42
⇔x-5=21
⇔ x=26
i) 3(x+7)-15=27
⇔ 3(x+7)=42
⇔ x+7=14
⇔ x=7
j) 15+4(x-2)=95
⇔ 4(x-2)=80
⇔ x-2=20
⇔ x=22
k) 20-(x+14)=5
⇔ x+14=15
⇔ x=1
l) 14+3(5-x)=27
⇔ 3(5-x)=13
⇔ 5-x=13/3
⇔ x=5-13/3
⇔ x=2/3
Bài 1
a, 32.(-64) - 64. 68
= -64.(32 + 68)
= -64 .100
= - 6400
b, -54.76 + 12.(-76) - 76.34
= -76.(54 + 12 + 34)
= -76.100
= -7600
19- 42.(-19) + 38.5
= 19 + 42.19 + 19.2.5
= 19.(1 + 42 + 10)
= 19.53
= 1007
ý bài này hỏi cái j hả bạn ?