14- ( 1,18 x X + 3,2 ) : 2= 6,5
14 - (1.18 x X +3.2) : 2 = 6.5
14-(1.18x X+3.2):2=6.5
(18x X+6):2 =14-6.5
(18x X+6):2 =7.5
18x X+6 =7.5x2
18x X+6 =15
18x X =15-6
18x X = 9
X = 9:18
X = 0.5
tính nhanh
13.5 x 5.1 +4.5 x7.8 x 3+ 12.9 * 6.5
1/3 x 46 + 2/3 * 37
3.2 * 950 + 8 *187 * 4 - 320 * 8.2
giúp mình nhé mình cần rất gấp
1/3 x 46 +2/3x37 3,2x (95x10) +(8x4)x 187 -(32x 10) x 8,2
=(1/3+2/3) x (46+37) 32x95+32x 187- 32x 82
= 1x 100 32x( 95+187-82)
= 100 = 32 x200
= 6400
Bài 2 tìm x ,biết:
a)3x-105:21=19
b)x-7=14-3.2 mũ 3
a)3x - 105 : 21 = 19
3x - 5 = 19
3x = 19 + 5
3x = 24
x = 24 : 8
x = 3
b, x - 7 = 14 - 3 . 23
x - 7 = 14 - 3 . 8
x - 7 = 14 - 24
x - 7 = -10
x = (-10) + 7
x = -3
HT và $$$
Bài 2:
a) 3x - 105 : 21= 19 b) x - 7= 14 - 3 . 2^3
3x - 5 = 19 x - 7= 14 - 3.8
3x = 19+ 5 x - 7= 14 - 24
3x = 24 x - 7= -10
x = 24 : 3 x = -10+7
x = 8 x = -3
1/Tính :
a. A= 1/17+ 7/17.27 + 7/27.37 + .................... +7/1997.2007
b. B=-1/2007.2006 - 1/2005.2006 - 1/2005.2004 - .................... - 1/3.2 - 1/2.1
2/Tim x biết :
2/(x+2)(x+4) + 4/(x+4)(x+8) + 6/(x+8)(x+14) = x/(x+2)(x+14)
Với x không thuộc tập hợp {-2;-4;-6;-8;-14}
A = 7/7.17 + 7/17.27 + 7/27.37 + ............ +7/1997.2007
A=7/10 ( 10/7.17 + 10/17.27 + 10/27.37 + ................+10/1997.2007)
A= 7/10 ( 1/7 -1/17 + 1/17 - 1/27 + 1/27 - 1/37 +...............+ 1/1997 - 1/2007)
A= 7/10 (1/7 - 1/2007)
A= 7/10 . 2000/14049
A=200/2007
bây h mk có vc rùi tích đúng nha tối mk lm típ cho
2/2/3:x=1/7/9:0,02
-3/5:3/14+0,5.x=12
2^2x+1=2^3.2^4
|3-x|+1/2=5
\(2\frac{2}{3}:x=1\frac{8}{9}:0,02\)
\(\frac{8}{3}:x=\frac{17}{9}:\frac{1}{50}\)
\(\frac{8}{3}:x=\frac{17}{9}.50\)
\(\frac{8}{3}:x=\frac{850}{9}\)
\(x=\frac{8}{3}:\frac{850}{9}\)
\(x=\frac{8}{3}x\frac{9}{850}\)
\(x=\frac{12}{425}\)
Vậy \(x=\frac{12}{425}\)
\(-\frac{3}{5}:\frac{3}{14}+0,5.x=12\)
\(-\frac{3}{5}:\frac{3}{14}+\frac{1}{2}.x=12\)\(-\frac{3}{5}x\frac{14}{3}+\frac{1}{2}.x=12\)\(-\frac{14}{5}+\frac{1}{2}.x=12\)\(\frac{1}{2}.x=12-\left(-\frac{14}{5}\right)\)\(\frac{1}{2}.x=12+\frac{14}{5}\)\(\frac{1}{2}.x=\frac{60}{5}+\frac{14}{5}\)\(\frac{1}{2}.x=\frac{74}{5}\) \(x=\frac{74}{5}:\frac{1}{2}\) \(x=\frac{74}{5}x2\) \(x=\frac{158}{5}\) Vậy \(x=\frac{158}{5}\)Dạng 2 : Tìm x Bài 1: Tìm x biết :
a) ( x – 16 ) – 74 = 0 b) (3 x – 5) .7 mũ 3 = 7 mũ 4
c) 560 – 13x = 365 d) 275 – 7( x + 1) = 100
e) 3 x 7 14 3.2 mũ 3 f) 7x – 49 = 105
g) 5x – 16 = 14 h) 3x – 138 = 23 . 2 2
Tìm x biết
10 + 2 . x = 4⁵ : 4³
2 x - 6² : 18 = 3.2²
70 - 5 . ( x- 3 ) = 3.2
\(10+2\cdot x=4^5:4^3\)
\(\Rightarrow10+2\cdot x=4^{5-3}\)
\(\Rightarrow10+2\cdot x=4^2\)
\(\Rightarrow10+2\cdot x=16\)
\(\Rightarrow2\cdot x=16-10\)
\(\Rightarrow2\cdot x=6\)
\(\Rightarrow x=\dfrac{6}{2}=3\)
__________________
\(2\cdot x-6^2:18=3\cdot2^2\)
\(\Rightarrow2\cdot x-36:18=12\)
\(\Rightarrow2\cdot x-2=12\)
\(\Rightarrow2\cdot x=12+2\)
\(\Rightarrow2\cdot x=14\)
\(\Rightarrow x=\dfrac{14}{2}=7\)
_________________
\(70-5\cdot\left(x-3\right)=3\cdot2\)
\(\Rightarrow70-5\cdot\left(x-3\right)=6\)
\(\Rightarrow70-5x+15=6\)
\(\Rightarrow-5x+15=6-70\)
\(\Rightarrow-5x+15=64\)
\(\Rightarrow-5x=64-15\)
\(\Rightarrow-5x=49\)
\(\Rightarrow x=-\dfrac{49}{5}\)
Tìm x
a) 197 -9 ( x+3) =80
b) 7 (x- 14) + 35 = 56
c) 2.3x+1 =54
d) 3.2x-1 =24
a)197-9(x+3)=80
=>9(x+3)=197-80
=>9(x+3)=117
=>x+3=117:9
=>x+3=13
=>x=13-3=10
b)7(x-14)+35=56
=>7(x+14)=56-35
=>7(x+14)=21
=>x+14=21/7
=>x+14=3
=>x=3-14=(-11)
c)2.3x-1=54
=>3x-1=54:2
=>3x-1=27
=>3x-1=33
=>x-1=3
=>x=3+1=4
d)3.2x-1=24
=>2x-1=24:3
=>2x-1=8
=>2x-1=23
=>x-1=3
=>x=3+1=4
\(a,197-9\left(x+3\right)=80\)
\(197-\left(9x+27\right)=80\)
\(197-9x-27=80\)
\(197-9x=107\)
\(9x=90\)
\(x=10\)
\(b,7\left(x-141\right)+35=56\)
\(7x-987+35=56\)
\(7x=56-35+987\)
\(7x=1008\)
\(x=144\)
197 - 9 . ( x + 3 ) = 80
9 . ( x + 3 ) = 197 - 80
9 . ( x + 3 ) = 117
x + 3 = 117 : 9
x + 3 = 13
x = 13 - 3
x = 10
7 . ( x - 14 ) + 35 = 56
7 . ( x - 14 ) = 56 - 35
7 . ( x - 14 ) = 21
x - 14 = 21 : 7
x - 14 = 3
x = 3 + 14
x = 17
1) tim x biết:
a) (19.x +2.5^2) : 14=(13-8)^2 - 4^2
b) 2.3^x=10.3^12+8.27^4
2) so sanh
a) 5^23 va 6.5^22
b)21^15 va 27^5.49^8
c)3^39 va 11^21
d) 7.2^13 va 2^16
1/Hãy tính giá trị của biểu thức sau:
a)1500-{5^3.2^3-11.[7^2-5.2^3+8(11^2-129)]}
b)3^2.10^3-[13^2-(5^2.4+2^2.15)].10^3
2/tìm x
a){[2.x+14:2^2-3]:2}-1=0
b)10-{[x:3+17):10+3.2^4]:10}=5
dấu chấm là dấu nhân nha
còn đây ^ là dấu mũ.
mình đang cần gấp ,mong các bạn giải giúp mình.Thank you