(-5).(-7)=?
(-6).(-5)=?
ai giup minh voi
lam giup minh voi.minh can gap
a) -12 . ( x - 5 ) + 7 .( -x + 3 ) = 5
b) 30 . (x + 2 )- 6 .( x - 5 ) - 24 .x = 100
ai nhanh nhat mk se k.lam on giup minh voi
\(a,-12.\left(x-5\right)+7.\left(-x+3\right)=5\)
\(-12x+60-7x+21=5\)
\(-19x+81=5\)
\(-19x=5-81\)
\(-19x=-76\)
\(x=4\)
\(b,30.\left(x+2\right)-6.\left(x-5\right)-24.x=100\)
\(30x+60-6x+30-24x=100\)
\(0x+90=100\)
\(0x=100-90\)
\(0x=10\)
=> ko có giá trị nào thõa mãn x
ai biet giup minh voi
| - 18 | + ( - 12) va 2^3 .2^2+ 5^7 : 5^5 - 3^2 .6
va tim x biet
3^10 : ( 43- 4x ) = 3^7
Tinh tong :
A = 1/1*3 + 1/3*5 + 1/5*7 + ..... + 1/99*101
B = 1 + 1/3 + 1/6 + 1/10 + ..... + 1/630
Giup minh voi nha ! Ai dung minh *** cho !
Giai ro rang ho minh voi !
B = \(1+\frac{1}{3}+\frac{1}{6}+....+\frac{1}{630}=1+\frac{2}{6}+\frac{2}{12}+...+\frac{2}{1260}\)
B = \(1+2\left(\frac{1}{2.3}+\frac{1}{3.4}+...+\frac{1}{35.36}\right)\)
B = \(1+2\left(\frac{1}{2}-\frac{1}{3}+\frac{1}{3}-\frac{1}{4}+...+\frac{1}{35}-\frac{1}{36}\right)\)
B = \(1+2\left(\frac{1}{2}-\frac{1}{36}\right)=1+2.\frac{17}{36}\)
B = \(1+\frac{17}{18}\)
B = \(\frac{35}{18}\)
\(A=\frac{1}{1x3}+\frac{1}{3x5}+\frac{1}{5x7}+...+\frac{1}{99x101}\)
\(A\)\(x2=\frac{2}{1x3}+\frac{2}{3x5}+\frac{2}{5x7}+...+\frac{2}{99x101}\)
\(A\)\(x2=1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+...+\frac{1}{99}-\frac{1}{101}\)
\(A\)\(x2=1-\frac{1}{101}=\frac{100}{101}\)
\(A=\frac{100}{101}:2=\frac{100}{101}x\frac{1}{2}=\frac{50}{101}\)
Ai lam giup minh bai nay voi.
-1+2+3-4-5+6+7-8-9+...+2011-2012-2013
Chi minh lam bai nay voi, xin may ban do
ai do giai giup minh voi...!
bai2: tinh gia tri bieu thuc: 9/11*(6/7-5/6) lam kieu gi
giup minh voi
minh tich 5 ban thoi nha
\(\dfrac{9}{11}\times\left(\dfrac{6}{7}-\dfrac{5}{6}\right)\)
\(=\dfrac{9}{11}\times\left(\dfrac{36}{42}-\dfrac{35}{42}\right)\)
\(=\dfrac{9}{11}\times\dfrac{1}{42}\)
\(=\dfrac{3}{154}\)
1/2 , 5/6 , 4/5, 7/8 , 6/7 va 8/9
Sap xep theo thu tu tu be den lon
Giup minh voi
Ta xét phần bù nhé :
\(\frac{1}{2}=\frac{1}{2}\); \(\frac{5}{6}=\frac{1}{6}\); \(\frac{4}{5}=\frac{1}{5}\); \(\frac{7}{8}=\frac{1}{8}\); \(\frac{6}{7}=\frac{1}{7}\); \(\frac{8}{9}=\frac{1}{9}\)
Phân số nào có phần bù lớn hơn thì phân số đó bé .
Ta sẽ sắp xếp như sau :
\(\frac{1}{2};\frac{4}{5};\frac{5}{6};\frac{6}{7};\frac{7}{8};\frac{8}{9}\).
.
1.Tinh
a,5/6+1/2
b,7/8+1/4
c,5/9+3/7
giup minh voi minh xin cam on
a, 5/6 + 1/2 = 5/6 + 3/6 = 8/6 = 4/3
b, 7/8 + 1/4 = 7/8 + 2/8 = 9/8
c, 5/9 + 3/7 = 35/63 + 27/63 = 62/63
100+99+88+77+.....+7+6+5+4+3+2+1
Tinh nhanh
Ai giup mk voi
<=> SSH:( 100 - 1 ) : 1 + 1 = 100
=> Tổng ( 100 + 1 ) . 100 : 2 = 5050
Vậy tổng đó bằng 5050