72 : x+180 : x=6
2 : Tìm X
a) x - 13 = - 46
b) 4 x - 6 = 22
3 : Tìm ƯCLN
a) 32 và 48
16 và 72
b) Tìm BCNN
24 và 60
72 và 180
2.
a, x-13=-46
=>x=(-46)+13
=>x=33
b, 4x-6=22
=>4x=22+6
=>4x=28
=>x=28:4
=>x=7
3.
a, 32=25
48=24.3
=>ƯCLN(32,48)=24=16
16=24
72=23.32
=>ƯCLN(16,72)=23=8
b,
24=23.3
60=22.3.5
=>BCNN(24,60)=23.3.5=120
72=23.32
180=22.32.5
=>BCNN(72,180)=23.32.5=360
a) x - 13 = - 46
x = - ( 46 + 13 )
x = - 59
Chắc vậy
3.x-72=180
\(\Rightarrow3x=180+72\\ \Rightarrow x=252:3\\ \Rightarrow x=84\)
⇒ \(3.x=180+72\)
⇒ \(3.x=252\)
⇒ \(x=84\)
3.x-72=180
\(3x=180+72\\ \Leftrightarrow x=\dfrac{252}{3}=84\)
Tính nhanh :
a . 29 x 64 + 116 x 34
b . 136 x 68 + 16 x 272
Tim x
c 180 - 23 x ( x - 5 )
d ( x - 280 ) x 35 = 54
g x - 280 : 35 = 54
e 12 x ( x - 6 ) : 4 = 72
a ; 29 x 64 +116 x 34
= 29 x 2 x 32 + 116 : 2 x 2 x 34
= 58 x 32 + 58 x 68
= 58 ( 32 + 68)
= 58 x 100
= 5800
b, 136 x 68 + 16 x 272
= 136 x 68 + 16 x 2 x 136
= 136 x 68 + 136 x 32
= 136 ( 68 + 32)
= 136 x 100
= 13600
123-5.(x+4)=38
(3.x-2^4).7^3=2.7^4
6^2:4.3+2.5^2
5.4^2-18:3^2
80-(4.5^2-3.2^3)
23.75+25.23+180
2448:[119-(23-6)]
Tim so nhien x biet
(2600+6400)-3.x=1200
[(6.x-72):2-84].28=562
123-5.(x+4)=38
5.(x+4)=123-38
5.(x+4)=85
x+4=85:5
x+4=17
x=17-4
x=13
(3.x-2^4).7^3=2.7^4
(3.x-16).343=2.2401
(3.x-16).343=4802
3.x-16=4802:343
3.x-16=14
3.x=14+16
3.x=30
x=30:3
x=10
6^2:4.3+2.5^2
=36:4.3+2.25
=9.3+2.25
=27+50
=77
5.4^2-18:3^2
=5.16-18:9
=80-2
=78
80-(4.5^2-3.2^3)
=80-(4.25-3.8)
=80-(100-24)
=80-76
=4
23.75+25.23+180
=23.(75+25)+180
=23.100+180
=2300+180
=2480
2448:[119-(23-6)]
=2448:(119-17)
=2448:102
=24
(2600+6400)-3.x=1200
9000-3.x=1200
3.x=9000-1200
3.x=7800
x=7800:3
x=2600
[(6.x-72):2-84].28=562
(6.x-72):2-84=562:28
(6.x-72):2-84=281/14
(6.x-72):2=281/14+84
(6.x-72):2=1457/14
6.x-72=1457/14.2
6.x-72=1457/7
6.x=1457/7+72
6.x=1961/7
x=1961/7:6
x=1961/42
Gọi vận tốc ban đầu của ô tô là x (x>0), ta có
\(1+\frac{10}{60}+\frac{180-x}{x+6}=\frac{180}{x}\)
\(\Leftrightarrow\frac{7}{6}+\frac{180-x}{x+6}=\frac{180}{x}\)
\(\Leftrightarrow\frac{7\left(x+6\right)}{6\left(x+6\right)}+\frac{6\left(180-x\right)}{6\left(x+6\right)}=\frac{180}{x}\)
\(\Leftrightarrow\frac{1122+x}{6x+36}=\frac{180}{x}\)
\(\Leftrightarrow x^2+1122x=1080x+6480\)
\(\Leftrightarrow x^2+42x-6480=0\)
Tính delta phẩy ra hai nghiệm
\(\orbr{\begin{cases}x_1=-21+3\sqrt{769}\left(TM\right)\\x_2=-21-3\sqrt{769}\left(loai\right)\end{cases}}\)
Vậy....
tinh nhanh 72 x 19 + 36 x 6 x 10 + 144 x 40 - 72 x 29
`= 72 xx 19 + 36 xx 2 xx3 xx 10 + 72 xx 80 - 72 xx 29`
`= 72 xx(19 + 30 - 29 + 80)`
`= 72 xx 100`
`= 7200`
\(=72.19+36.2.3.10+72.2.40-72.29\)
\(=72.19+72.30+72.80-72.29\)
\(=72.\left(19+30+80-29\right)\)
\(=72.100=7200\)
Tính họp li?
1, (158 x 129 - 158 x 39) : 180
2, 102- 96 +90-84+78-72+66-60+54-48
Ai làm nhanh va dung mk tick cho
( 158 x 129 - 158 x 39 ) : 180
= [ 158 x ( 129 - 39 ) ] : 180
= [ 158 x 90 ] : 180
= 14220 : 180
= 79
1) ( 158 x 129 - 158 x 39 ) : 180
= [158 x (129 - 39 ) ] : 180
= 158 x 90 : 180
= 158 x ( 90 : 180 )
= 158 x 1/2
= 158 : 2
= 79.
2)102- 96 +90-84+78-72+66-60+54-48
= ( 102 - 72 ) + ( -96 + 66 ) + ( 90 - 60 ) + ( -84 + 54 ) + ( 78 - 48 )
= 30 - 30 + 30 - 30 + 30 = 30
1) ( 158 x 129 - 158 x 39 ) : 180
= [158 x (129 - 39 ) ] : 180
= 158 x 90 : 180
= 158 x ( 90 : 180 )
= 158 x 1/2
= 158 : 2
= 79.
2)102- 96 +90-84+78-72+66-60+54-48
= ( 102 - 72 ) + ( -96 + 66 ) + ( 90 - 60 ) + ( -84 + 54 ) + ( 78 - 48 )
= 30 - 30 + 30 - 30 + 30 = 30
Tìm x :
c 180 - 23 x ( x - 5 )
d ( x - 280 ) x 35 = 54
g x - 280 : 35 = 54
e 12 x ( x - 6 ) : 4 = 72
d) => x-280 = 54:35=54/35
=> x = 54/35 +280=9854/35
g) x-8 = 54
=> x = 54+8 = 66
e) x-6 = 72 .4 :12=24
=> x = 24+6=30