\(\left(84,6-2\cdot x\right):3,02=5,1\)
\(\Rightarrow84,6-2\cdot x=15,402\)
\(\Rightarrow2\cdot x=69,198\)
\(\Rightarrow x=69,198:2\)
\(\Rightarrow x=34,599\)
_____________
\(\left(15\cdot24-x\right):0,25=100:0,25\)
\(\Rightarrow\left(360-x\right):0,25=400\)
\(\Rightarrow360-x=100\)
\(\Rightarrow x-360-100\)
\(\Rightarrow x=260\)
______________
\(128\cdot x-12\cdot x-16\cdot x=5200\)
\(\Rightarrow x\cdot\left(128-12-16\right)=5200\)
\(\Rightarrow x\cdot100=5200\)
\(\Rightarrow x=5200:100\)
\(\Rightarrow x=52\)
__________________
\(5\cdot x+3,75\cdot x+1,25\cdot x=20\)
\(\Rightarrow x\cdot\left(5+3,75+1,25\right)=20\)
\(\Rightarrow10\cdot x=20\)
\(\Rightarrow x=20:10\)
\(\Rightarrow x=2\)
\(x\cdot3,7+x\cdot6,3=360:120\)
\(\Rightarrow x\cdot\left(3,7+6,3\right)=3\)
\(\Rightarrow x\cdot10=3\)
\(\Rightarrow x=\dfrac{3}{10}\)
__________________
\(x\cdot23-6\cdot23+x\cdot69=320\)
\(\Rightarrow x\cdot\left(23+69\right)=320+6\cdot23\)
\(\Rightarrow x\cdot92=458\)
\(\Rightarrow x=458:92\)
\(\Rightarrow x=\dfrac{229}{46}\)
___________________
\(\left(x+1\right)\left(x+2\right)=72\)
\(\Rightarrow x^2+2x+x+2=72\)
\(\Rightarrow x^2+3x+2=72\)
\(\Rightarrow x^2+3x+2-72=0\)
\(\Rightarrow x^2+3x-70=0\)
\(\Rightarrow x^2+10x-7x-70=0\)
\(\Rightarrow\left(x-7\right)\left(x+10\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=7\\x=-10\end{matrix}\right.\)
___________________
\(\left(x+2\right)\cdot16\cdot x=160x\)
\(\Rightarrow16x^2+32x=160x\)
\(\Rightarrow16x^2+32x-160x=0\)
\(\Rightarrow16x^2-128x=0\)
\(\Rightarrow16x\left(x-8\right)=0\)
\(\Rightarrow\left[{}\begin{matrix}x=0\\x=8\end{matrix}\right.\)
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
a.(84,6-2. x ):3,02=5,1
=>84,6 - 2x = 15,402
=>2x=69,198
=>x=34,599
b.(15.24-x):0,25=100:0,25
=>(360-x) : 0,25 = 400
=>360-x = 400 . 0,25
=>360-x=100
=>x=360-100
=>x=260
c.128.x-12.x-16.x=5200
=>(128-12-16)x=5200
=>100x=5200
=>x=52
d.5.x+3,75.x+1,25.x=20
=>(5+3,75+1,25)x=20
=>10x=20
=>x=2
e.x.3,7+x.6,3=360:120
=>x(3,7+6,3)=3
=>10x=3
=>x=3/10
f.x.23-6.23+x.69=230
=>23x + 6.23 + 3x . 23 = 230
=>23.(x+6+3x)=230
=>4x+6=10
=>4x=10-6
=>4x=4
=>x=1
g.(x+1).(x+2)=72
TH1:x là số dương
=>(x+1)(x+2)=8.9
=>x+1=8
=>x=7
TH2:x là số âm
=>(x+1)(x+2)=(-9).(-8)
=>x+1=-9
=>x=-10
Vậy x=-10 hoặc x=7
h.(x+2).16.x=160.x
=>x+2 = 160.x:x:16
=>x+2=10
=>x=8
a.(84,6-2. x ):3,02=5,1
=>84,6 - 2x = 15,402
=>2x=69,198
=>x=34,599
b.(15.24-x):0,25=100:0,25
=>(360-x) : 0,25 = 400
=>360-x = 400 . 0,25
=>360-x=100
=>x=360-100
=>x=260
c.128.x-12.x-16.x=5200
=>(128-12-16)x=5200
=>100x=5200
=>x=52
d.5.x+3,75.x+1,25.x=20
=>(5+3,75+1,25)x=20
=>10x=20
=>x=2
e.x.3,7+x.6,3=360:120
=>x(3,7+6,3)=3
=>10x=3
=>x=3/10
f.x.23-6.23+x.69=230
=>23x - 6.23 + 3x . 23 = 230
=>23.(x-6+3x)=230
=>4x-6=16
=>4x=10+6
=>4x=16
=>x=4
g.(x+1).(x+2)=72
TH1:x là số dương
=>(x+1)(x+2)=8.9
=>x+1=8
=>x=7
TH2:x là số âm
=>(x+1)(x+2)=(-9).(-8)
=>x+1=-9
=>x=-10
Vậy x=-10 hoặc x=7
h.(x+2).16.x=160.x
=>(16x+32).x=160x
=>16x^2 + 32x - 160x = 0
=>16x^2 -128x=0
=>x(16x - 128)=0
=>x=0 hoặc 16x-128=0
16x-128=0
=>16x=128
=>x=8
Vậy x = 0 hoặc 8
Sửa yêu cầu. Tìm x (không phải tính nhanh)
(84,6 - 2.x) : 3,02 = 5,1
84,6 - 2x = 5,1 . 3,02
84,6 - 2x = 15,402
2x = 84,6 - 15,402
2x = 69,198
x = 69,198 : 2
x = 34,599
--------------------
(15.24 - x) : 0,25 = 100 : 0,25
(360 - x) : 0,25 = 400
360 - x = 400 . 0,25
360 - x = 100
x = 360 - 100
x = 260
--------------------
128.x - 12.x - 16.x = 5200
(128 - 12 - 16)x = 5200
100x = 5200
x = 5200 : 100
x = 52
--------------------
5.x + 3,75.x + 1,25.x = 20
(5 + 3,75 + 1,25)x = 20
10x = 20
x = 20 : 10
x = 2
--------------------
x.3,7 + x.6,3 = 360 : 120
(3,7 + 6,3)x = 3
10x = 3
x = 3/10
--------------------
x.23 - 6.23 + x.69 = 230
(23 + 69)x = 230 + 6.23
92x = 230 + 138
92x = 368
x = 368 : 92
x = 4
--------------------
(x + 1)(x + 2) = 72
x² + 2x + x + 2 - 72 = 0
x² + 3x - 70 = 0
x² - 7x + 10x - 70 = 0
(x² - 7x) + (10x - 70) = 0
x(x - 7) + 10(x - 7) = 0
(x - 7)(x + 10) = 0
x - 7 = 0 hoặc x + 10 = 0
*) x - 7 = 0
x = 7
*) x + 10 = 0
x = -10
Vậy x = -10; x = 7
--------------------
(x + 2).16.x = 160x
16x² + 32x - 160x = 0
16x² - 128x = 0
16x(x - 8) = 0
16x = 0 hoặc x - 8 = 0
*) 16x = 0
x = 0
*) x - 8 = 0
x = 8
Vậy x = 0; x = 8
a.(84,6-2. x ):3,02=5,1
=>84,6 - 2x = 15,402
=>2x=69,198
=>x=34,599
b.(15.24-x):0,25=100:0,25
=>(360-x) : 0,25 = 400
=>360-x = 400 . 0,25
=>360-x=100
=>x=360-100
=>x=260
c.128.x-12.x-16.x=5200
=>(128-12-16)x=5200
=>100x=5200
=>x=52
d.5.x+3,75.x+1,25.x=20
=>(5+3,75+1,25)x=20
=>10x=20
=>x=2
e.x.3,7+x.6,3=360:120
=>x(3,7+6,3)=3
=>10x=3
=>x=3/10
f.x.23-6.23+x.69=230
=>23x + 6.23 + 3x . 23 = 230
=>23.(x+6+3x)=230
=>4x+6=10
=>4x=10-6
=>4x=4
=>x=1
g.(x+1).(x+2)=72
TH1:x là số dương
=>(x+1)(x+2)=8.9
=>x+1=8
=>x=7
TH2:x là số âm
=>(x+1)(x+2)=(-9).(-8)
=>x+1=-9
=>x=-10
Vậy x=-10 hoặc x=7
h.(x+2).16.x=160.x
=>x+2 = 160.x:x:16
=>x+2=10
=>x=8
