X x 2 + 3,4 X x + X x 0,5 = 21,83
8,75 x X + 1,25 x X = 20
4,5 x x = 352,1 - 191,9
( 74,2 + 6,3 ) : x = 23
0,12 x x = 3,6 + 2,4
( 74,2 + 6,3 ) : = 23
8,75 x x + 1,25 x x =20
Mọi người giúp rùm
a\ x-3,45=90,45:15
b\ 3/5:x=1/2+2
c\ 12:9-x=16*0,25
d\ 12,5-x=10-5,73
e\18,2:x=1,4*4
f\ 4*x=658,2-251,8
g\ x*4,5=352,1-191,9
a) x - 3,45 = 90,45 : 15
x - 3,45 = 6,03
x = 6,03 + 3,45
x = 9,48
Vậy x = 9,48
b) 3/5 : x = 1/2+ 2
3/5 : x = 5/2
x = 3/5 : 5/2
x = 6/25
Vậy x = 6/25
13,5 . x - 125 = 16,75
( 74,2 + 6,3 ) : x = 23
3/4 . 12/5 + x = 5/2
44/7 : 63/11 - x = 2/3
Mọi người giúp mik với huhu help my huhu
Bài 1 tính nhanh ( đầy đủ ). ( dấu chấm là dấu nhân )
(84,6-2. x ):3,02=5,1
(15.24-x):0,25=100:0,25
128.x-12.x-16.x=5200
5.x+3,75.x+1,25.x=20
x.3,7+x.6,3=360:120
x.23-6.23+x.69=230
(x+1).(x+2)=72
(x+2).16.x=160.x
\(\left(84,6-2\cdot x\right):3,02=5,1\)
\(\Rightarrow84,6-2\cdot x=15,402\)
\(\Rightarrow2\cdot x=69,198\)
\(\Rightarrow x=69,198:2\)
\(\Rightarrow x=34,599\)
_____________
\(\left(15\cdot24-x\right):0,25=100:0,25\)
\(\Rightarrow\left(360-x\right):0,25=400\)
\(\Rightarrow360-x=100\)
\(\Rightarrow x-360-100\)
\(\Rightarrow x=260\)
______________
\(128\cdot x-12\cdot x-16\cdot x=5200\)
\(\Rightarrow x\cdot\left(128-12-16\right)=5200\)
\(\Rightarrow x\cdot100=5200\)
\(\Rightarrow x=5200:100\)
\(\Rightarrow x=52\)
__________________
\(5\cdot x+3,75\cdot x+1,25\cdot x=20\)
\(\Rightarrow x\cdot\left(5+3,75+1,25\right)=20\)
\(\Rightarrow10\cdot x=20\)
\(\Rightarrow x=20:10\)
\(\Rightarrow x=2\)
\(x\cdot3,7+x\cdot6,3=360:120\)
\(\Rightarrow x\cdot\left(3,7+6,3\right)=3\)
\(\Rightarrow x\cdot10=3\)
\(\Rightarrow x=\dfrac{3}{10}\)
__________________
\(x\cdot23-6\cdot23+x\cdot69=320\)
\(\Rightarrow x\cdot\left(23+69\right)=320+6\cdot23\)
\(\Rightarrow x\cdot92=458\)
\(\Rightarrow x=458:92\)
\(\Rightarrow x=\dfrac{229}{46}\)
___________________
\(\left(x+1\right)\left(x+2\right)=72\)
\(\Rightarrow x^2+2x+x+2=72\)
\(\Rightarrow x^2+3x+2=72\)
\(\Rightarrow x^2+3x+2-72=0\)
\(\Rightarrow x^2+3x-70=0\)
\(\Rightarrow x^2+10x-7x-70=0\)
\(\Rightarrow\left(x-7\right)\left(x+10\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=7\\x=-10\end{matrix}\right.\)
___________________
\(\left(x+2\right)\cdot16\cdot x=160x\)
\(\Rightarrow16x^2+32x=160x\)
\(\Rightarrow16x^2+32x-160x=0\)
\(\Rightarrow16x^2-128x=0\)
\(\Rightarrow16x\left(x-8\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=8\end{matrix}\right.\)
Đổi:
f.x.23-6.23+x.69=230
=>23.(x-6+3x)=230
=>4x-6=10
=>4x=10+6
=>4x=16
=>x=4
h.(x+2).16.x=160.x
=>(16x+32).x = 160x
=>16x^2 + 32x = 160x
=>16x^2 = 128x
=>16x^2 - 128x=0
=>x(16x-128)=0
=>x=0 hoặc 16x-128=0
+)x=0=>x=0
+)16x-128=0
=>16x=128
=>x=8
Tính bằng cách thuận tiện nhất:
a) 1,25 x 5 x 6,3 : 0,125 x 2
b) 12,5 x 6,9 + 0,1 x 6,9 x 865 + 6,9
\(a.1,25\times5\times6,3\div0,125\times2\\ =\left(5\times2\right)\times\left(1,25\div0,125\right)\times6,3\\ =10\times10\times6,3=630\)
\(b.12,5\times6,9+0,1\times6,9\times865\times6,9\\ =6,9\times\left(12,5+86,5+1\right)\\ =6,9\times100=690\)
Tính thuận tiện :
a, 4,2 x 1,25 + 0,6 x 9,25 x 7- 2,1 x 1,75 x 2
b, 0,68 x 900 - 2 x 75 x 3,4 phần 4,5 - 4 - 3,5 - 3 + 2,5 - 2 + 1,5 - 1 + 0,5
c, 9,8 : 2,5 + 12,4 : 2,5 - 1,5 : 2,5
d, 19,8 : 0,25 x 7,2 : 0,125 x 8,4 : 0,5 phần 6,6 x 8 x 2,4 x 4 x 16,8 : 0,2
tui cũng hỏi giống bạn nhưng không ai giai cho tui cả huhu
Tính bằng cách thuận tiện nhât:
a) 16,24 x 12 – 1,624 x 10 x 3+ 16,24
=
b) 1,25 + 1,25 x 2 + 7 x 1,25
=
c) 2,46 : 0,5 + 2,46 x 8
=
a, \(=16,24\left(12-3+1\right)\)
\(=16,24.10=162,4\)
b, \(=1,25\left(1+2+7\right)\)
\(=1,25.10=12,5\)
c, \(=2,46\left(2+8\right)\)
\(=2,46.10=24,6\)
\(a,=16,24\times12-16,24\times3+16,24\times1\\ =16,24\times\left(12-3+1\right)=16,24\times10=162,4\\ b,=1,25\times\left(1+2+7\right)=1,25\times10=12,5\)
a 16.24( 12-10+3)=16.24 x 5=81.2
b 1.25(1+2+7)=1.25 x 10= 12.5
c 2.46 x 2 + 2.46 x8 = 2.46(2 + 8)=2.46 x 10=24.6
0,8 x 0,5 x 1,25 x 2,5 x 2 x 0,4
0,8 x 0,5 x 1,25 x 2,5 x 2 x 0,4
= (0,8 x 1,25) x (0,5 x 2) x (2,5 x 0,4)
= 1 x 1 x 1
= 1
Tính bằng cách thuận tiện nhất:
a) 1,25 + 1,25 x 2 + 7 x 1,25
b) 3,62 x 12 – 2 x 0,362 x 10
c) 12,35 x 15 – 1,235 x 10 x 6 + 12,35
d) 1,42 : 0,5 + 1,42 x 8