tìm x
(70-20)*x=100
Tìm x, biết
a) 70 - (x - 3) = 45; b) 12 + (5 + x) = 20
c) 130 - (100 + x) = 25; d)175 + (30 - x) = 200
e) (x + 12) + 22 = 92; f) 95 - (x + 2) = 45
a) \(70-\left(x-3\right)=45\)
\(x-3=70-45\)
\(x-3=25\)
\(x=25+3\)
\(x=28\)
b) \(12+\left(5+x\right)=20\)
\(5+x=20-12\)
\(5+x=8\)
\(x=8-5\)
\(x=3\)
c) \(130-\left(100+x\right)=25\)
\(100+x=130-25\)
\(100+x=105\)
\(x=105-100\)
\(x=5\)
d) \(175+\left(30-x\right)=200\)
\(30-x=200-175\)
\(30-x=25\)
\(x=30-25\)
\(x=5\)
e) \(\left(x+12\right)+22=92\)
\(x+12=92-22\)
\(x+12=70\)
\(x=70-12\)
\(x=58\)
f) \(95-\left(x+2\right)=45\)
\(x+2=95-45\)
\(x+2=50\)
\(x=50-2\)
\(x=48\)
a)
70 - (x - 3) = 45
x - 3 = 70 - 45 = 25
x = 25 + 3 = 28
Vậy x = 28
b)
12 + (5 + x) = 20
5 + x = 20 - 12 = 8
x = 8 - 5 = 3
Vậy x = 3
c)
130 - (100 + x) = 25
100 + x = 130 - 25 = 115
x = 115 - 100 = 15
Vậy x = 15
d)
175 + (30 - x) = 200
30 - x = 200 - 175 = 25
x = 30 - 25 = 5
Vậy x = 5
e)
(x + 12) + 22 = 92
x + 12 = 92 - 22 = 70
x = 70 - 12 = 58
Vậy x = 58
f)
95 - (x + 2) = 45
x + 2 = 95 - 45 = 50
x = 50 - 2 = 48
Vậy x = 48
Tìm x, biết:
a) 400 – x.3 = 100;
b) 250 : x + 10 = 20;
c) 96 – 3( x + 8) = 42;
d) 36:(x – 5) = 22;
e) 15.5.(x – 35) – 525 = 0;
f) [3.(70 – x) + 5]: 2 = 46
B=/2x-100/ +/200-2x/ tìm GTNN cua B
C=/x-70/+/20+x/ timf GTNN cua C
D=/x-80/+/x-200/ timfGTTN cua D
Bài 1.Tìm x biết
a,70-5(x-3)=45
b,12+(5+x)=20
c,130-(100 + x)=25
a,70-5(x-3)=45
5(x-3) = 70 - 45
5(x-3) = 25
x-3 = 25 : 5
x - 3 = 5
x = 5 + 3
x = 8.
b,12+(5+x)=20
(5+x) = 20 - 12
(5+x) = 8
x = 8 - 5
x = 3
c,130-(100 + x)=25
100 + x = 130 - 25
100 + x = 105
x = 105 - 100
x = 5
Hok tốt !
a,70-5(x-3)=45
5(x-3) =70-45
5(x-3) =25
(x-3) =25:5
x-3 =5
x=5+3
x=8
a,70-5(x-3)=45
5(x-3)=70-45
5(x-3)=25
x-3=25:5
x-3=5
x=5+3
x=8
Vậy x=8
b,12+(5+x)=20
5+x=20-12
5+x=8
x=8-5
x=3
Vậy x=3
c,130-(100 + x)=25
100+x=130-25
100+x=105
x=105-100
x=5
Vậy x=5
tìm X
70-5(x-3)=45
12+(5+x)=20
130-(100+x)=25
175+(30-x)=200
5(x+12)+22=92
a) \(70-5\left(x-3\right)=45\)
\(5\left(x-3\right)=25\)
\(x-3=5\)
\(\Rightarrow x=8\)
b) \(12+\left(5+x\right)=20\)
\(5+x=8\)
\(\Rightarrow x=3\)
c) \(130-\left(100+x\right)=25\)
\(100+x=105\)
\(\Rightarrow x=5\)
d) \(175+\left(30-x\right)=200\)
\(30-x=25\)
\(\Rightarrow x=5\)
e) \(5\left(x+12\right)+22=92\)
\(5\left(x+12\right)=70\)
\(x+12=14\)
\(\Rightarrow x=2\)
a. 70 - 5.(x - 3) = 45
5.(x - 3) = 70 - 45
x - 3 = 25 : 5
x = 5 + 3
x = 8
b. 12 + (5 + x) = 20
5 + x = 20 - 12
x = 8 - 5
x = 3
c. 130 - (100 + x) = 25
100 + x = 130 - 25
x = 105 - 100
x = 5
d. 175 + (30 - x) = 200
30 - x = 200 - 175
x = 30 - 25
x = 5
e. 5.(x + 12) + 22 = 92
5.(x + 12) = 92 - 22
x + 12 = 70 : 5
x = 14 - 12
x = 2
300 : x - 20 : x = 70
x - 63 × 11 = 156 × 402
x : 100 = 15,6
300 : x - 20 : x = 70
=> (300-20):x =70
=> 280 : x= 70
=> x = 280 : 70 = 4
x-63.11 = 156.402
=> x-693 = 62712
=> x=62712+69363405
x : 100 = 15,6
=> x=15,6 . 100 = 1560
Bài 8. Tìm các số tự nhiên x, sao cho : a) x E B(11) và 20 < x < 100. b) x E Ư(32) và x > 4. c) x E B(14) và 28 E x < 80. d) x E 13 và 10 < x E 70.
tìm x
(-270:x+20=-70
\(\dfrac{-270}{x}+20=-70\)
\(⇔\dfrac{-270}{x}=-70-20\)
\(⇔x=\dfrac{-270}{-70-20}\)
\(⇔x=3\)
Tìm x (x-20):(x-10)=(x+40):(x+70)
ĐKXĐ: \(\hept{\begin{cases}x\ne10\\x\ne-70\end{cases}}\)
\(\frac{x-20}{x-10}=\frac{x+40}{x+70}\)
\(\Rightarrow\left(x-20\right)\left(x+70\right)=\left(x+40\right)\left(x-10\right)\)
\(\Rightarrow x^2+70x-20x-1400=x^2-10x+40x-400\)
\(\Rightarrow20x=1000\Rightarrow x=50\)
Vậy x = 50