Tính nhanh:
a. 256 x 82 + 18 x 256
b. 56 x 211 + 211 x 43 +211
Tìm x, biết:
a) x = 1 5 + 2 11
b) x 5 = 5 6 + − 19 30
a) x = 1 5 + 2 11 ⇔ x = 1.11 + 2.5 55 = 21 55
b) x 5 = 5 6 + − 19 30 ⇔ x 5 = 5.5 + ( − 19 ) 30 = 6 30 = 1 6 ⇔ x = 5 6
Điền dấu > , < , = :
9999 ...10 000
653 211....653 211
99 999 ...100 000
43 256... 432 510
726 585...557 652
845 713...854 713
9999 < 10 000
653 211 = 653 211
99 999 < 100 000
43 256 < 432 510
726 585 > 557 652
845 713 < 854 713
Điền dấu > , < , = :
9999 ...10 000
653 211....653 211
99 999 ...100 000
43 256... 432 510
726 585...557 652
845 713...854 713
9999 < 10 000
653 211 = 653 211
99 999 < 100 000
43 256 < 432 510
726 585 > 557 652
845 713 < 854 713
9999<10000
653211=653211
99999<100000
43256<4325`10
726585>557652
845713<854713
253 - (-76 + 253) + 99
68 - (199 + 68) - (-150)
211 - (107 + 211) - 23
-(-345 + 56 - 267) + (453 - 124 - 843)
-25 - (34 - 256 + 67) - (-2) + (-10 - 65)
253 - (-76 + 253) + 99 =175
68 - (199 + 68) - (-150) = -49
211 - (107 + 211) - 23 = -130
-(-345 + 56 - 267) + (453 - 124 - 843) =42
-25 - (34 - 256 + 67) - (-2) + (-10 - 65) =57.
\(\text{217-x/207+215-x/209+213-x/211+211-x/213+4=0}\)
\(\frac{217-x}{207}+\frac{215-x}{209}+\frac{213-x}{211}+\frac{211-x}{213}+4=0\)
\(\Leftrightarrow\)\(\left(\frac{217-x}{207}+1\right)+\left(\frac{215-x}{209}+1\right)+\left(\frac{213-x}{211}+1\right)+\left(\frac{211-x}{213}+1\right)=0\)
\(\Leftrightarrow\)\(\frac{424-x}{207}+\frac{424-x}{209}+\frac{424-x}{211}+\frac{424-x}{213}=0\)
\(\Leftrightarrow\)\(\left(424-x\right)\left(\frac{1}{207}+\frac{1}{209}+\frac{1}{211}+\frac{1}{213}\right)=0\)
\(\Leftrightarrow\)\(424-x=0\) (do 1/207 + 1/209 + 1/211 + 1/213 # 0)
\(\Leftrightarrow\)\(x=424\)
Vậy...
Tìm x, biết:
a ) x = 1 5 + 2 11 ; b ) x = 1 13 + − 13 26 ; c ) x = 1 12 + 3 4 + − 2 9 ;
d ) x 5 = 5 6 + − 19 30 ; e ) x 7 = 3 7 + − 5 4 ; f ) 11 8 + 13 6 = 85 x ;
a ) x = 21 55 ; b ) x = − 11 26 ; c ) x = 11 18 ; d ) x = 1
d ) x = − 1 ; e ) x = 11 7 ; f ) x = 20
Rút gọn biểu thức: a) 2x + (-461) - (231 - 461); b) ( -83 - x + 45) + 83 c) 211- (123 - x) + (123 - 211); d) 25- ( 125 - x + 32) + 22
Bài 1 : Rút gọn biểu thức :
a) 2x + (- 461) - ( 231 - 461 )
b) ( - 83 - x + 45) + 83
c) 211 - (123 - x ) + ( 123 - 211)
d) 25 - ( 125 - x +32) + 22
Tính giá trị của biểu thức ;
A=2/1/547 x 3/211 - 546/547 x 1/211 - 4/547x211