6/7x5/8x7/3x7/6x8/5=?
7x5=
2x9=
3x7=
tk cho mk nha! Đừng tk sai cho mk nhé !
7x5=35
2x9=27
3x7=21
tk cho mk nha rùi mk tk lại cho
5/6 : 1/6% - 4 % = ... ( SỐ THẬP PHÂN )
4/2X4 + 4/6X8 ....... 4/180X182 =
tính bằng cách thuận tiện nhất:
a 1+2+3+4+5+6+7+8+9
b 8x3+8x7
c 8x172-8x72
a)1+2+3+4+5+6+7+8+9
=(1+9)+(2+8)+(3+7)+(4+6)+5
=10+10+10+10+5
=10x4+5=45
b)8x3+8x7
=8x(3+7)
=8x10=80
c)8x172-8x72
=8x(172-72)
=8x100=800
a. 1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 +9
= (1 + 9) + (2 + 8) + (3 + 7) + ( 4 + 6) + 5
= 10 + 10 + 10 + 10 + 5
= 45
Tính nhanh: (8x7-16-5x8)x(1+2+3+4+5+6+7+8+9)
=(8*7-8*2-8*5)*((1+9)+(2+8)+(3+7)+(4+6)+5)
=(8*(7-2-5))*(10+10+10+10+5)
=(8*0)*(10+10+10+10+5)
=0*(10+10+10+10+5)
=0
tính nhanh
(8x7-16-5x8)x (1+2+3+4+5+6+7+8+9)
1+3+5+7+9+11+13+15+17+19
(8 x 7 - 16 - 5 x 8) x (1 + 2 + 3 + 4 + 5 + 6 + 7 + 8 + 9)
= [8 x 7 - 8 x 2 - 5 x 8] x [(1 + 9) + (2 + 8 ) + (3 + 7) + (4 + 6) + 5]
= [8 x (7 - 2 - 5)] x [10 + 10 + 10 + 10 + 10 + 5]
= (8 x 0) x 45
= 0
1 + 3 + 5 + 7 + 9 + 11 + 13 + 15 + 17 + 19
= (1 + 9) + (3 + 7) + (5 + 15) + (11 + 19) + (13 + 17)
= 10 + 10 + 20 + 30 + 30
= 100
a) 5/6 : 1/12% - 5 % = ... ( số thập phân )
b) 2/2x4 + 2/6x8 + ... 2/188 x 190 = .... ( phân số )
b)\(=\frac{1}{2}-\frac{1}{4}+\frac{1}{4}-\frac{1}{6}+...+\frac{1}{188}-\frac{1}{190}\)
\(=\frac{1}{2}-\frac{1}{190}\)
\(=\frac{47}{95}\)
10x+3/12=1+6:8x/9
2x+7x5 5x+1=0
2x(x-5)-x+5=0
(x+3)^2-(5-x)(x+3)=0
(x+2)(3-4x)=x^2+4x+4
bạn viết rõ đề câu a;b nhé
c, \(2x\left(x-5\right)-\left(x-5\right)=0\Leftrightarrow\left(2x-1\right)\left(x-5\right)=0\Leftrightarrow x=\dfrac{1}{2};x=5\)
d, \(\left(x+3\right)\left(x+3-5+x\right)=0\Leftrightarrow\left(x+3\right)\left(2x-2\right)=0\Leftrightarrow x=-3;x=1\)
e, \(\left(x+2\right)\left(3-4x\right)=\left(x+2\right)^2\Leftrightarrow\left(x+2\right)\left(3-4x-x-2\right)=0\)
\(\Leftrightarrow\left(x+2\right)\left(-5x+1\right)=0\Leftrightarrow x=-2;x=\dfrac{1}{5}\)
a.7/12+-5/8+2/3
b.2/7+3/4
c.-5/6+2/9+7/12
d.-5/6-7/8
e.-2/13-3/7+-2/3x7/7
f.(-5,6)x2+7,8
g.2,8:(-0,7)
tham khảo
a. 5/8
b. 29/28
c. -1/36
d. -41/24
e. -341/273
f. -17/5
g. -4
5/8x20/9+5/8x7/9+ 1 và 5/8
\(\dfrac{5}{8}\times\dfrac{20}{9}-\dfrac{5}{8}\times\dfrac{7}{9}+1\)
\(=\dfrac{5}{8}\times\left(\dfrac{20}{9}-\dfrac{7}{9}\right)+1\)
\(=\dfrac{5}{8}\times\dfrac{13}{9}+1\)
\(=\dfrac{65}{72}\)
Ta có: \(\dfrac{5}{8}=\dfrac{45}{72}\)
Mà: \(65>45\)
Vậy: \(\dfrac{65}{72}>\dfrac{45}{72}\) hay \(\dfrac{5}{8}\times\dfrac{20}{9}+\dfrac{5}{8}\times\dfrac{7}{9}+1>\dfrac{5}{8}\)