-17 . (25 - 43 ) + 25 . (34 + 17 ) - 19 -193
tìm chữ số tận cùng của các tổng sau
43^43+17^17+19^23
34^15+25^9+41^41
4343 + 1717 + 1923 có chữ số tận cùng là 3
3415 + 159 + 4141 có chữ số tận cùng là 0
Câu 1 : tính nhanh
a) ( -7) . 11 + 7 . ( - 89 )
b) ( -57) . ( 67 - 34) - 67 . ( 34 - 57 )
c) ( 17 - 25 ) - ( - 37 - 25 + 17 )
d) - ( -72 - 25 + 17 ) + ( - 72 + 17 )
e) ( -25 ) . ( -13) .8 (-4).125
f) 38 . (-43) + 43 . (-79) - (-43) . 17
e, (-25).(-13).8.(-4).125
= (-25).(-4).8.125.(-13)
= 100.1000.(-13)=-1300000
f, 38.(-43)+43.(-79)-(-43).17
= 38.(-43)+(-43).79-(-43).17
= (-43).(38+79-17)
= (-43).100=-4300
a) ( -7) . 11 + 7 . ( - 89 )
= 7 . (-11) + 7 . (-89)
= 7 . [(-11)+(-89)]
= 7 . (-100)
= -700
b, (-57).(67-34)-67.(34-57)
= -57.67+57.34-67.34+67.57
= 34(57-67)=34.(-10)=-340
c, (17-25)-(-37-25+17)
= 17-25+37+25-17
=37
d, -(-72-25+17)+(-72+17)
= 72+25-17-72+17= 25
tìm số nguyên x
-2x-(x-17)=34-(-x+25)
17x-(16x-37)=2x+43
-2x-3(x+17)=34-2(-x+25)
17x+3(16x-37)=2x+43-14x
-2x+15<3x-7<19-x
25+24+23+.....+x+(x-2)+(x-3)
nhanh lên nha
\(-2x-\left(x-17\right)=34-\left(-x+25\right)\)
\(-2x-x+17=34+x-25\)
\(-2x-x-x=34-25-17\)
\(-4x=-8\Leftrightarrow x=2\)
\(17x-\left(16x-37\right)=2x+43\)
\(17x-16x+37=2x+43\)
\(17x-16x-2x=-37+43\)
\(-x=6\Leftrightarrow x=6\)
\(-2x-3\left(x+17\right)=34-2\left(-x+25\right)\)
\(-2x-3x-51=34+2x-50\)
\(-2x-3x-2x=34-50+51\)
\(-7x=35\Leftrightarrow x=-5\)
Tìm chữ số tận cùng của cấ số sau :
4343+1717-1923
3415-259+4141
A=[(2/193-3/386).193/17+33/34]:[(7/2001+11/4002).2001/25+9/2]
Bài làm
\(A=\left[\left(\frac{2}{193}-\frac{3}{386}\right).\frac{193}{17}+\frac{33}{34}\right]:\left[\left(\frac{7}{2001}+\frac{11}{4002}\right).\frac{2001}{25}+\frac{9}{2}\right]\)
\(=\left[\frac{1}{386}.\frac{193}{17}+\frac{33}{34}\right]:\left[\frac{25}{4002}.\frac{2001}{25}+\frac{9}{2}\right]\)
\(=\left[\frac{1}{34}+\frac{33}{34}\right]:\left[\frac{1}{2}+\frac{9}{2}\right]\)
\(=\frac{1}{5}\)
E = [193/-17 ( 2/193 - 3/386 ) + 11/34] : [(7/1931 + 11/3862) 1931/25 +9/2]
Tính: [(7/2001 + 11/4002) . 2001/25 + 9/2]:[(2/193 - 3/386) . 193/17 + 33/34]
giải giúp tui với ạ
M=[(2/193-3/386).193/17+33/34]:[(7/2001+11/4002).2001/25+9/2]
\(M=\left[\left(\dfrac{2}{193}-\dfrac{3}{386}\right)\cdot\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\left(\dfrac{7}{2001}+\dfrac{11}{4002}\right)\cdot\dfrac{2001}{25}+\dfrac{9}{2}\right]\)
\(M=\left[\left(\dfrac{4}{386}-\dfrac{3}{386}\right)\cdot\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\left(\dfrac{14}{4002}+\dfrac{11}{4002}\right)\cdot\dfrac{2001}{25}+\dfrac{9}{2}\right]\)
\(M=\left(\dfrac{1}{386}\cdot\dfrac{193}{17}+\dfrac{33}{34}\right):\left(\dfrac{25}{4002}\cdot\dfrac{2001}{25}+\dfrac{9}{2}\right)\)
\(M=\left(\dfrac{1}{34}+\dfrac{33}{34}\right):\left(\dfrac{1}{2}+\dfrac{9}{2}\right)\)
\(M=1:5\)
\(M=\dfrac{1}{5}\)
\(=\left[\dfrac{4-3}{386}\cdot\dfrac{193}{17}+\dfrac{33}{34}\right]:\left[\dfrac{25}{4002}\cdot\dfrac{2001}{25}+\dfrac{9}{2}\right]\)
\(=\left(\dfrac{1}{34}+\dfrac{33}{34}\right):\left[\dfrac{1}{2}+\dfrac{9}{2}\right]\)
=1/5
a) -2x-(x-17)=34-(-x 25)
b) 17x-(-16x-27)=2x 43
c) -2x-3(x-17)=34-2(-x 25)
d) 17x +3(-16x-37)=2x 43-4x
a) -2x - (x-17) = 34-(-x + 25)
-2x- x+17= 34+x-25
-2x-x-x= -17 +34-25
-4x = -8
x = 2
b)17x-(-16x-27) = 2x+43
17x + 16x + 27 = 2x + 43
17x + 16x -2x= -27 +43
31x= 26
x= 21/31
c)- 2x- 3(x-17) = 34- 2(-x + 25)
-2x - 3x + 51 = 34 + 2x -50
-2x - 3x -2x = -51 + 34 -50
-7x = -67
x = 67/7
d) 17x +3(-16x-37) = 2x+ 43 -4x
17x -48x -111 = 2x + 43 -4x
17x - 48x -2x + 4x = 111 -43
-29x = 68
x = -68/29