7 X 3 =
7 x 2 = ..... 7 x 4 = ..... 7 x 6 = ..... 7 x 3 = .....
2 x 7 = ..... 4 x 7 = ..... 6 x 7 = ..... 3 x 7 = .....
14 : 7 = ..... 28 : 7 = ..... 42 : 7 = ..... 21 : 7 = .....
14 : 2 = ..... 28 : 4 = ..... 42 : 6 = ..... 21 : 3 = .....
7 x 2 = 14 7 x 4 = 28 7 x 6 = 42 7 x 3 = 21
2 x 7 = 14 4 x 7 = 28 6 x 7 = 42 3 x 7 = 21
14 : 7 = 2 28 : 7 = 4 42 : 7 = 6 21 : 7 = 3
14 : 2 = 7 28 : 4 = 7 42 : 6 = 7 21 : 3 = 7
Tính nhẩm:
7 x 2 =
4 x 7 =
7 x 6 =
3 x 7 =
5 x 7 =
2 x 7 =
7 x 4 =
6 x 7 =
7 x 3 =
7 x 5 =
7 x 2 = 14
4 x 7 = 28
7 x 6 = 42
3 x 7 = 21
5 x 7 = 35
2 x 7 = 14
7 x 4 = 28
6 x 7 = 42
7 x 3 = 21
7 x 5 = 35
7 x 2 = 14
4 x 7 = 28
7 x 6 = 42
3 x 7 = 21
5 x 7 = 35
2 x 7 = 14
7 x 4 = 28
6 x 7 = 42
7 x 3 = 21
7 x 5 = 35
2\(^7\) + ( x - 3\(^7\) ) = 5\(^7\) - 4\(^7\)
3 \(^x\) - (x + 2 \(^x\)) = 7
7 \(^2\) - (15 + x) = 5.2 \(^2\)
7 \(^3\) - 7(13 - x) = 14
a: \(2^7+\left(x-3^7\right)=5^7-4^7\)
=>\(128+x-2187=78125-16384\)
=>\(x-2059=61741\)
=>\(x=61741+2059=63800\)
c: \(7^2-\left(x+15\right)=5\cdot2^2\)
=>49-(x+15)=5*4=20
=>x+15=29
=>x=14
d: 7^3-7(13-x)=14
=>343-7(13-x)=14
=>7(13-x)=343-14=329
=>13-x=47
=>x=13-47=-34
1) x+1/2=-5/3
2) 1/3-x=3/5
4) x-4/3=-7/9
5) x--7/3=5/6
6) x-1/5=9/10
7) x+5/12=3/8
8) x+5/4=7/6
9) x-2/7=1/35
10) x-2/7=-7/10
6: =>x=9/10+1/5=9/10+2/10=11/10
7: =>x=3/8-5/12=36/96-40/96=-1/24
8: =>x=7/6-5/4=14/12-15/12=-1/12
9: =>x=1/35+2/7=1/35+10/35=11/35
10: =>x=2/7-7/10=20/70-49/70=-29/70
1, \(x=-\dfrac{5}{3}-\dfrac{1}{2}=-\dfrac{10}{6}-\dfrac{3}{6}=-\dfrac{13}{6}\)
2, \(x=\dfrac{1}{3}-\dfrac{3}{5}=\dfrac{5-9}{15}=-\dfrac{4}{15}\)
4, \(x=-\dfrac{7}{9}+\dfrac{4}{3}=\dfrac{-7+12}{9}=\dfrac{5}{9}\)
5, \(x=\dfrac{5}{6}-\dfrac{7}{3}=\dfrac{5-14}{6}=-\dfrac{9}{6}=-\dfrac{3}{2}\)
6, \(x=\dfrac{9}{10}+\dfrac{1}{5}=\dfrac{9+2}{10}=\dfrac{11}{10}\)
7, \(x=\dfrac{3}{8}-\dfrac{5}{12}=\dfrac{9-10}{12}=-\dfrac{1}{12}\)
8, \(x=\dfrac{7}{6}-\dfrac{5}{4}=\dfrac{14-15}{12}=-\dfrac{1}{12}\)
9, \(x=\dfrac{1}{35}+\dfrac{2}{7}=\dfrac{1+10}{35}=\dfrac{11}{35}\)
10, \(x=-\dfrac{7}{10}+\dfrac{2}{7}=\dfrac{-49+20}{70}=\dfrac{-29}{70}\)
Viết số thích hợp vào chỗ chấm :
7 x 3 = ... 7 x 1 = ... 7 x 6 = ... 7 x 0 = ...
3 x 7 = ... 1 x 7 = ... 6 x 7 = ... 7 x 7 = ...
7 x 3 = 21 7 x 1 = 7 7 x 6 = 42 7 x 0 = 0
3 x 7 = 21 1 x 7 = 7 6 x 7 = 42 7 x 7 = 49
Viết số thích hợp vào ô trống:
7 x 2 = 2 x 6 x 7 = 7 x 3 x 7 = x 3
7 x 5 = 5 x 4 x 7 = 7 x 7 x 0 = x 7
7 x 2 = 2 x [7] 6 x 7 = 7 x [6] 3 x 7 = [7] x 3
7 x 5 = 5 x [7] 4 x 7 = 7 x [4] 7 x 0 = [0] x 7
1/ x + 1/2 = -5/3 6/ x - 1/5 = 9/10
2/ 1/3 - x = 3/5 7/ x + 5/12 = 3/8
3/ 3-4 + x = 7/2 8/ x + 5/4 = 7/6
4/ x - 4/3 = -7/9 9/ x - 2/7 = 1/35
5/ x - -7/3 = 5/6 10/ x - 1/5 = -7/10
\(1,\\ x+\dfrac{1}{2}=-\dfrac{5}{3}\\ x=-\dfrac{5}{3}-\dfrac{1}{2}\\ x=-\dfrac{13}{6}\\ Vậyx=-\dfrac{13}{6}\)
\(2,\\ \dfrac{1}{3}-x=\dfrac{3}{5}\\ x=\dfrac{1}{3}-\dfrac{3}{5}\\ x=-\dfrac{4}{15}\\ Vậyx=-\dfrac{4}{15}\)
\(3,\\ 3-4+x=\dfrac{7}{2}\\ -1+x=\dfrac{7}{2}\\ x=\dfrac{7}{2}+1\\ x=\dfrac{9}{2}\\ Vậyx=\dfrac{9}{2}\)
\(4,\\ x-\dfrac{4}{3}=-\dfrac{7}{9}\\ x=-\dfrac{7}{9}+\dfrac{4}{3}\\ x=\dfrac{15}{27}\\ Vậyx=\dfrac{15}{27}\)
\(5,\\ x-\left(-\dfrac{7}{3}\right)=\dfrac{5}{6}\\ x=\dfrac{5}{6}-\dfrac{7}{3}\\ x=-\dfrac{27}{18}\\ Vậyx=-\dfrac{27}{18}\)
\(6,\\ x-\dfrac{1}{5}=\dfrac{9}{10}\\ x=\dfrac{9}{10}+\dfrac{1}{5}\\ x=\dfrac{11}{10}\\ Vậyx=\dfrac{11}{10}\)
\(7,\\ x+\dfrac{5}{12}=\dfrac{3}{8}\\ x=\dfrac{3}{8}-\dfrac{5}{12}\\ x=-\dfrac{1}{24}\\ Vậyx=-\dfrac{1}{24}\)
\(8,\\ x+\dfrac{5}{4}=\dfrac{7}{6}\\ x=\dfrac{7}{6}-\dfrac{5}{4}\\ x=-\dfrac{9}{24}\\ Vậyx=-\dfrac{9}{24}\)
\(9,\\ x-\dfrac{2}{7}=\dfrac{1}{35}\\ x=\dfrac{1}{35}+\dfrac{2}{7}\\ x=\dfrac{11}{35}\\ Vậyx=\dfrac{11}{35}\\ 10,\\ x-\dfrac{1}{5}=-\dfrac{7}{10}\\ x=-\dfrac{7}{10}+\dfrac{1}{5}\\ x=-\dfrac{1}{2}\\ Vậyx=-\dfrac{1}{2}\)
ahiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii hãy ấn a
1) x+1/2=-5/3
2) 1/3-x=3/5
4) x-4/3=-7/9
5) x--7/3=5/6
6) x-1/5=9/10
7) x+5/12=3/8
8) 5/4=7/6
9) x-2/7=1/35
10) x-2/7=-7/10
cả phép tính nữa nha
1: =>x=-5/3-1/2=-13/6
2: =>x=1/3-3/5=-4/15
4: =>x=-7/9+4/3=-7/9+12/9=5/9
5: =>x=5/6-7/3=5/6-14/6=-9/6=-3/2
6: =>x=9/10+1/5=11/10
7: =>x=3/8-5/12=36/96-40/96=-1/24
8: Đề sai rồi bạn
X-7 = -5 (x+2) = 0 (3x - 24) . 73 =2.74 | x - 5 | = |-7| x- [42 + ( -28) = -8 ( 7x - x ) - ( 25+7 ) = -25 |x-3| = |5| + | -7 | ( x : 3-4 ) : 5 =15 | x -3 | = 7 - (-2) 128 -3 . (x+4) = 23 4 - ( 7-x ) = x - (13-4 ) BÀI 2 : TÍNH NHANH S1 = 1+2+3+.......999 S1= 10 +12 + 14 +.......2010 S3 + 21 + 23 + 25 + .......10001
tìm x thuộc Z biết:
1) 2(4x-8)-7(3+x)=[-4](3-2)
2) 12(x-4)+6(x-2)-16(x+3)=7[-4]
3) 4(x-5)-7(5-x)+10(5-x)=-3
4) -3[x+5]=15(-3)+7(-3)
5) 4[x-7]-3(-5)=-2[x-7]-10
1) <=> 8x-16-21-7x=-4
<=> x-37=-4
<=> x=33
2) <=> 12x-48+6x-12-16x-48=-28
<=> 2x-108=-28
<=> 2x = 80
<=> x = 40
3)<=> 4x-20-35+7x+50-10x=-3
<=> x-5=-3
<=> x=2
4) <=> -3x-15=-45-21
<=> 51=3x
<=> 17=x
5) 4x-28+15=-2x+14-10
<=> 6x-13=4
<=> 6x=17
<=> x = \(\frac{17}{6}\)
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