(x+2)+(x+4)+(x+6)+(x+8)+x=120
[x+2] + [x+4] + [x+6] + [x+8] + x = 120
(x+2)+(x+4)+(x+6)+(x+8)+x=120
(x+x+x+x+x)+(2+4+6+8)=120
5x+20=120
5x=120-20
5x=100
x=100:5
x=20
Vậy x=20
\(\left(x+2\right)+\left(x+4\right)+\left(x+6\right)+\left(x+8\right)+x=120\)
\(\left(x+x+x+x+x\right)+\left(2+4+6+8\right)=120\)
\(x.5+20=120\)
\(x.5=120-20\)
\(x.5=100\)
\(x=100:5\)
\(x=20\)
[ x + 2 ] + [ x + 4 ] + [ x + 6 ] + [ x + 8 ] + x = 120
[ x + 2 ] + [ x + 4 ] + [ x + 6 ] + [ x + 8 ] + [ x + 10 ] = 120
[ x + ( 2 + 4 + 6 + 8 + 10 ) ] = 120
x + 30 = 120
x = 120 : 30
x = 4.
(x+2)+(x+4)+(x+6)+(x+8)+x=120
(x+2)+(x+4)+(x+6)+(x+8)+x=120
( x + x + x + x + x ) + ( 2 + 4 + 6 + 8 ) = 120
5x + 20 = 120
5x = 120 - 20
5x = 100
x = 100 : 5
x = 20
(x+2)+(x+4)+(x+6)+(x+8)+x=120
120=5x+(2+4+6+8)
120=5x+20
=>5x=120-20
=>5x=100
=>x=100:5
=>x=20
vậy x=20.
tính thuận tiện :
0,8 x 120 + 4 x 2 x 6 +8 x 2 +8 x 80
Giải :
0,8 x 120 + 4 x 2 x 6 +8 x 2 +8 x 80
= 8 x 12 + 8 x 6 + 8 x 2 + 8 x 80
= 8 x ( 12 + 6 + 2 + 80 )
= 8 x 100
= 800
= 800 nha bạn
hok tốt
bạn nào trên 10 sp hoặc 10 sp k giúp mình ạ
sp á
là ...
điểm hỏi đáp k đúng đi
1. x - 8 +32= 68
2. x +8+32=68
3. 98-x +34=43
4. 98+x-34=43
5. x :5:4=800
6. 18+x=384:8
7. (84,6-2 x x):3,02= 5,1
8. x x5= 120:6
9. (15x 24-x) :0,25= 100:0,25
1. \(x-8+32=68\)
\(x-8=68-32\)
\(x-8=36\)
\(x=36+8\)
\(x=44\)
_____
2. \(x+8+32=68\)
\(x+8=68-32\)
\(x+8=36\)
\(x=36-8\)
\(x=28\)
_____
3. \(98-x+34=43\)
\(98-x=43-34\)
\(98-x=9\)
\(x=98-9\)
\(x=89\)
_____
4. \(98+x-34=43\)
\(98+x=43+34\)
\(98+x=77\)
\(x=77-98\)
\(x=-21\)
_____
5. \(x:5:4=800\)
\(x:5=800.4\)
\(x:5=3200\)
\(x=3200.5\)
\(x=16000\)
_____
6. \(18+x=384:8\)
\(18+x=48\)
\(x=48-18\)
\(x=30\)
_____
7. \(\left(84,6-2\times x\right):3,02=5,1\)
\(84,6-2.x=5,1.3,02\)
\(84,6-2.x=15,402\)
\(2.x=84,6-15,402\)
\(2.x=69,198\)
\(x=69,198:2\)
\(x=34,599\)
_____
8. \(x\times5=120:6\)
\(x.5=20\)
\(x=20:5\)
\(x=4\)
_____
9. \(\left(15\times24-x\right):0,25=100:0,25\)
\(\left(15.24-x\right):0,25=400\)
\(15.24-x=400.0,25\)
\(15.24-x=100\)
\(360-x=100\)
\(x=360-100\)
\(x=260\)
1,x-8+32=68
=>x-8=68-32=36
=>x=36+8=42
2,x+8+32=68
=>x+8=68-32=36
=>x=36-8=28
3,98-x+34=43
=>98-x=43-34=9
=>x=98-9=89
4,98+x-34=43
=>98+x=43+34=77
=>x=77-98=-21
5,x:5:4=800
=>x:20=800
=>x=800x20=16000
6,18+x=384:8=48
=>x=48-18=30
7,(84,6-2x):3,02=5,1
=>84,6-2x=5,1x3,02=15,402
=>2x=84,6-15,402=69,198
=>x=69,198:2=34,599
8,5x=120:6=20
=>x=20:5=4
9,(15x24-x):0,25=100:0,25=400
=>360-x=400x0,25=100
=>x=360-100=260.
1. \(...\Rightarrow x+24=68\Rightarrow x=68-24=44\)
2. \(...\Rightarrow x+40=68\Rightarrow x=68-40=28\)
3. \(...\Rightarrow3^{2\left(8+x\right)}=9=3^2\Rightarrow2\left(8+x\right)=2\Rightarrow8+x=1\Rightarrow x=-7\)
4. \(...\Rightarrow3^{2\left(8+x\right)}=77\) (bạn xem lại đề)
5. \(...\Rightarrow x:5=800.4\Rightarrow x:5=3200\Rightarrow x=3200.5=16000\)
6. \(...\Rightarrow18+x=48\Rightarrow x=48-18=30\)
7. \(...\Rightarrow84,6-2x=5,1.3,02=15,402\Rightarrow2x=84,6-15,402\Rightarrow2x=69,198\Rightarrow x=34,599\)
8. \(...\Rightarrow5.x=20\Rightarrow x=20:5=4\)
9. \(\left(360-x\right):0,25=400\Rightarrow360-x=400.0,25=100\Rightarrow x=400-100=300\)
Cho ( x + 2) + (x + 4) + (x + 6) + (x + 8) + x = 120. Giá trị của x là
\(\left(x+2\right)+\left(x+4\right)+\left(x+6\right)+\left(x+8\right)+x=120\)
\(\left(x+x+x+x+x\right)+\left(2+4+6+8\right)=120\)
\(x\times5+20=120\)
\(x\times5=120-20\)
\(x\times5=100\)
\(x=100:5\)
\(x=20\)
\(\left(x+2\right)+\left(x+4\right)+\left(x+6\right)+\left(x+8\right)+x=120\)
\(x+2+x+4+x+6+x+8+x=120\)
\(\left(x+x+x+x+x\right)+\left(2+4+6+8\right)=120\)
\(5x+20=120\)
\(5x=100\)
\(x=20\)
Tìm X
a,(x+1)+(x+2)+(x+3)+...+(x+9)+(x+10)=240
b.(x+2)+(x+4)+(x+6)+(x+8)+X=120
a,(x+1)+(x+2)+(x+3)+....+(x+9)+(x+10)=240
Từ 1 đến 10 có số số hạng là:(10-1):1+1=10
Từ 1 đến 10 có tổng là:(10+1)x10:2=55
Ta có:(Xx10)+55=240
Xx10 =240-55
Xx10 =185
X =185:10
X =18,5
ĐẠI SỐ 7
Rút gọn : A = 4^6 x 9^5 + 6^9 x 120 / 6^11 - 8^4 x 3^12
B = 2^12 x 3^5 - 4^6 x 9^2 / ( 2^2 x 3 )^6 + 8^4 x 3^5
-----------------------------------------------------
Ai làm dc thì giúp mình nheee )) Camon :))
tính hợp lí: 10 x 4^6 x 9^5+ 6^9 x 120 : 8^4 x 3^12 - 6^11
\(\dfrac{10.4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}=\dfrac{5.2.2^{12}.3^{10}+3^9.2^9.2^3.3.5}{2^{12}.3^{12}-2^{11}.3^{11}}\)
\(=\dfrac{5.2^{13}.3^{10}+2^{12}.3^{10}.5}{2^{11}.3^{11}\left(2.3-1\right)}=\dfrac{2^{12}.3^{10}.5\left(2+1\right)}{2^{11}.3^{11}.5}\)
\(=\dfrac{2^{11}.2.3^{10}.5.3}{2^{11}.3^{10}.3.5}=2\)
2. tìm x
a) \(\left(x-1\right)^3=8\)
b) \(7^{2x-6}=49\)
c) \(\left(2x-14\right)^7=128\)
d) \(x^4.x^5=5^3.5^6\)
e) \(\left[3.\left(x+2\right):7\right].4=120\)
a) \(\left(x-1\right)^3=8=2^3\)
\(x-1=2\)
\(x=2+1=3\)
b) \(7^{2x-6}=49=7^2\)
\(2x-6=2\)
\(2x=6+2=8\)
\(x=8:2=4\)
c) \(\left(2x-14\right)^7=128=2^7\)
\(2x-14=2\)
\(2x=14+2=16\)
\(x=16:2=8\)
d) \(x^4\cdot x^5=5^3\cdot5^6=5^4\cdot5^5\)
\(x=5\)
e) \(3\cdot\left(x+2\right):7\cdot4=120\)
\(x+2=120:3\cdot7:4\)
\(x+2=70\)
\(x=70-2=68\)
Lời giải:
a. $(x-1)^3=8=2^3$
$\Rightarrow x-1=2$
$\Rightarrow x=3$
b. $7^{2x-6}=49=7^2$
$\Rightarrow 2x-6=2$
$\Rightarrow 2x=8$
$\Rightarrow x=4$
c. $(2x-14)^7=128=2^7$
$\Rightarrow 2x-14=2$
$\Rightarrow 2x=16$
$\Rightarrow x=18$
d.
$x^4.x^5=5^3.5^6$
$x^9=5^9$
$\Rightarrow x=5$
e.
$3(x+2):7=120:4=30$
$3(x+2)=30.7=210$
$x+2=210:3=70$
$x=70-2=68$