1+1=?
2+2=?
3+3=?
4+4=?
5+5=?
giai nhanh nhe!
do nhe;
1+2+3+4+5+6+7....+99+10=
giai nhanh nhe
Bài đễ tui !!
Giải
Đưa phép tính về dạng này nhé : ( 1+2+3+4+5+6+7+...+99 ) + 10
Tính trong hoặc : +) ( 99 - 1 ) x 1 + 1 = 99 số
+) Kết quả là : ( 99 + 1 ) x 99 : 2 = 4950
+) 4950 + 10 = 4960
Đáp số 4960
Vậy 1+2+3+4+5+6+7+...+99+10 = 4960
Nếu số cuối là10 :1+2+3+4+5+6+7+....+99+10
Đặt a=1+2+3+4+5+6+7+.....+99
Số số hạng a là : (99-1):2+1=99 (số hạng)
Tổng a = (99+1)x99 : 2 = 4950
Thay a vào ta có : 4950 +10 =4960
tim x biet : 1-(3/4+x-2/3):4/5=0
giai nhanh len nhe
a. x \(\div\)( 1/1*3 + 1/3*5 + ...... + 1/101*103 ) =1 .
b.( 1/1*2 + 1/2*3 + 1/3*4 + ........ + 1/11*12) * x =2
c. x : 3/4 = 2x * 7/3 +5
Cac ban giai theo dang tim x nha . Cam on nhieu. Nhanh nhe vi minh can gap
a) 5/6 x 11/4 - 5/4 x 23/6
b) 9/16 x 13/4 - 9/4 x 5/16 + 9/16 x 17/
hay tinh tong:
1/1 x 2 + 1/2 x 3 + 1/3 x 4 + .... + 1/n (n + 1)
chung minh:
1/22 + 1/32 + 1/42 + ..... + 1/n2 < 1
giai dum nhe
a)3/4 + 1/4.x + x - 7/6. x = 5/12
b)0,25.x - 2/3.x = -1 1/6
giai chi tiet nhe
\(\frac{3}{4}+\frac{1}{4}\cdot x+x-\frac{7}{6}\cdot x=\frac{5}{12}\)
\(\frac{3}{4}+\frac{1}{4}\cdot x-\frac{7}{6}\cdot x+x\cdot1=\frac{5}{12}\)
\(\frac{3}{4}+x\left(\frac{1}{4}-\frac{7}{6}+1\right)=\frac{5}{12}\)
\(\frac{3}{4}+x\cdot\frac{1}{12}=\frac{5}{12}\)
\(x\cdot\frac{1}{12}=\frac{5}{12}-\frac{3}{4}\)
\(x\cdot\frac{1}{12}=\frac{5}{12}-\frac{9}{12}\)
\(x\cdot\frac{1}{12}=\frac{-1}{3}\)
\(x=\frac{-1}{3}\text{ : }\frac{1}{12}\)
\(x=\frac{-1}{3}\cdot12\)
\(x=\frac{-12}{3}\)
\(x=-4\)
\(\text{b, }0,25\cdot x-\frac{2}{3}\cdot x=-1\frac{1}{6}\)
\(\frac{1}{4}\cdot x-\frac{2}{3}\cdot x=\frac{-7}{6}\)
\(x\cdot\left(\frac{1}{4}-\frac{2}{3}\right)=\frac{-7}{6}\)
\(x\cdot\frac{-5}{12}=\frac{-7}{6}\)
\(x=\frac{-7}{6}\text{ : }\frac{-5}{12}\)
\(x=\frac{-7}{6}\cdot\frac{12}{-5}\)
\(x=\frac{-14}{-5}\)
a ) x + 3 1/2 + x = 24 1/4
b) (2 4/5 * x - 50) : 2/3 = 51
Nhanh nhanh gium minh nhe
Tinh nhanh [1/1*3+1/3*5+1/5*7+1/7*9+1/9*11]*y=2/3
Giai ro rang ho minh nhe
(1/1*3 + 1/3*5 + 1/5*7 + 1/7*9 + 1/9*11) * y = 2/3
=> (1 - 1/3 + 1/3 - 1/5 + 1/5 - 1/7 + 1/7 - 1/9 + 1/9 - 1/11) * y = 2/3
=> (1 - 1/11) * y = 2/3
=> 10/11 * y = 2/3
=> y = 11/15
\(\left(\frac{1}{1\cdot3}+\frac{1}{3\cdot5}+\frac{1}{5\cdot7}+\frac{1}{7\cdot9}+\frac{1}{9\cdot11}\right)\cdot y=\frac{2}{3}\)
\(\left[\frac{1}{2}\left(\frac{2}{1\cdot3}+\frac{2}{3\cdot5}+\frac{2}{5\cdot7}+\frac{2}{7\cdot9}+\frac{2}{9\cdot11}\right)\right]\cdot y=\frac{2}{3}\)
\(\left[\frac{1}{2}\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+\frac{1}{9}-\frac{1}{11}\right)\right]\cdot y=\frac{2}{3}\)
\(\left[\frac{1}{2}\left(1-\frac{1}{11}\right)\right]\cdot y=\frac{2}{3}\)
\(\frac{1}{2}\cdot\frac{10}{11}\cdot y=\frac{2}{3}\)
\(\frac{5}{11}\cdot y=\frac{2}{3}\)
\(y=\frac{2}{3}\div\frac{5}{11}=\frac{22}{15}\)
\(\left(\frac{1}{1\times3}+\frac{1}{3\times5}+...+\frac{1}{9\times11}\right)\times y=\frac{2}{3}\)
=> \(\frac{1}{2}\times\left(\frac{2}{1\times3}+\frac{2}{3\times5}+...+\frac{2}{9\times11}\right)\times y=\frac{2}{3}\)
=> \(\left(1-\frac{1}{3}+\frac{1}{3}-\frac{1}{5}+...+\frac{1}{9}-\frac{1}{11}\right)\times y=\frac{2}{3}:\frac{1}{2}\)
=> \(\left(1-\frac{1}{11}\right)\times y=\frac{4}{3}\)
=> \(\frac{10}{11}\times y=\frac{4}{3}\)
=> \(y=\frac{22}{15}\)
1/ Tim x
a/x.(x+5) - (x-2)^2 = 4
b/ x.( x+5 ) ( x-5)- (x+2)(x^2 - 2x +4)= 3
c/(x-2)^2 -x (x-8)=12
d/(x-2)^2 -(x+2)^2=11
e/x^2 + 8x -9 = 0
Giai nhanh ho mk nhe
Mk camon