Tim x
a, ( - 14 - x ) + 13 = 5
b, ( 11 + x ) - ( - 11 - 9 ) = 32
c, 5 - ( x - 8 ) + ( - 21 ) = 42
d, - [ 4 - 15 ] - ( - 4 - x = - 45
e, - 23 - ( 10 - x ) = - 50
Tim X
3) -12 + (2x – 9) + x= 0
4) 11 + (15 - x) = 1
5) 4 - (27 - 3) = x - (13 - 4)
6) 8 - (x - 10) = 23 - (- 4 +12)
7) 105 – 5(10 – 5x) = -20
8) (x -1)(8-2x)(3x+123) = 0
9) (x2 - 25)(x+ 10) = 0
10) x(x2+5) =
3) \(-12+2x-9+x=0\\ -21+3x=0\\ 3x=21\\ x=7\)
4)
\(11+\left(15-x\right)=1\)
\(15-x=1-11\)
\(15-x=-10\)
\(x=15-\left(-10\right)\)
\(x=25\)
5)
\(4-\left(27-3\right)=x-\left(13-4\right)\)
\(4-24=x-9\)
\(x-9=-20\)
\(x=-20+9\)
\(x=-11\)
\(3.-12+\left(2x-9\right)+x=0.\)
\(\Leftrightarrow-12+2x-9+x=0.\Leftrightarrow3x=21.\Leftrightarrow x=7.\)
Vậy \(x=7.\)
\(4.11+\left(15-x\right)=1.\Leftrightarrow11+15-x=1.\Leftrightarrow26-x=1.\Leftrightarrow x=25.\)
Vậy \(x=25.\)
\(5.4-\left(27-3\right)=x-\left(13-4\right).\Leftrightarrow4-24=x-9.\Leftrightarrow-20=x-9.\Leftrightarrow x=-11.\)
Vậy \(x=-11.\)
\(6.8-\left(x-10\right)=23-\left(-4+12\right).\Leftrightarrow8-x+10=23-8.\Leftrightarrow18-x=15.\Leftrightarrow x=3.\)
Vậy \(x=3.\)
\(7.105-5\left(10-5x\right)=-20.\Leftrightarrow105-50+25x=-20.\Leftrightarrow25x=-75.\Leftrightarrow x=-3.\)
Vậy \(x=-3.\)
\(8.\left(x-1\right)\left(8-2x\right)\left(3x+123\right)=0.\)
\(\Leftrightarrow\left[{}\begin{matrix}x-1=0.\\8-2x=0.\\3x+123=0.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=1.\\x=4.\\x=-41.\end{matrix}\right.\)
Vậy \(x\in\left\{1;4;-41\right\}.\)
\(9.\left(x^2-25\right)\left(x+10\right)=0.\)
\(\Leftrightarrow\left(x-5\right)\left(x+5\right)\left(x+10\right)=0.\)
\(\Leftrightarrow\left[{}\begin{matrix}x-5=0.\\x+5=0.\\x+10=0.\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=5.\\x=-5.\\x=-10.\end{matrix}\right.\)
Vậy \(x\in\left\{5;-5;-10\right\}.\)
\(10.x\left(x^2+5\right)=0.\Leftrightarrow x=0.\)
Bài 1:
1) x + 13 = 21
2) - 41 + x = - 55
3) x + ( -15 ) = ( - 17 ) + ( - 4 )
4 ) 3 + x = ( - 8 ) + 11
5 ) x + 37 = - 104 + 6
6) x + ( - 71 ) = ( - 55 ) + 85
7 ) x - ( - 45 ) = - 63 + 27
8) x + 29 = 43 + ( - 23 )
9 ) x + ( - 47 ) = ( - 62 ) - 17
10 ) x + 21 = ( - 43 ) + 43
11 ) 31 + x = 45 - 81
12 ) x - 12 = ( - 8 ) + (- 7 )
13 ) 23 - x = 24 - ( - 16 )
14 ) - 15 - ( - 21 - 3x ) = - 63
15 ) 57 - ( x - 46 ) = - 13
16 ) -x - 23 = -38 - 42
17 ) x - ( - 7 ) = -4 - 14
18 ) 18 - x = -8 - ( - 15 )
19 ) 45 - ( x + 17 ) = - 26
20 ) 3. ( x + 5 ) - x - 11 = 24
21 ) 14 - ( x - 7 ) = - 8 - ( - 9 )
22 ) 15 - ( x - 2 ) = - 7 + 8
Đã học về số âm rùi nha
ai nhanh tick choo
dài quá làm hộ câu 1-5 thoy
1) x=21-13
x=8
2)x=-55+41
x=-14
3)x=-21+15
x=-6
4)x=3-3
x=0
5) x= -98-37
x=-135
15 ) 57 - ( x - 46 ) = - 13
57 - x + 46 = -13
103 - x = -13
x = 103 + 13
x = 116
16 ) -x - 23 = -38 - 42
- ( x + 23 )=- ( 38 + 42)
x + 23 = 38 + 42
x = 38 + 42 -23
x = 57
17 ) x - ( - 7 ) = -4 – 14
X + 7 = -18
X = -18-7
X = -25
18 ) 18 - x = -8 - ( - 15 )
18 – x = 7
X = 18 – 7
X = 11
19 ) 45 - ( x + 17 ) = - 26
45 – x - 17 = -26
28 – x = -26
X = 28 + 26
X = 54
20 ) 3. ( x + 5 ) - x - 11 = 24
3x +15 –x – 11 = 24
2x + 4 =24
2x = 24 – 4
2x = 20
X = 20 : 2
X = 10
21 ) 14 - ( x - 7 ) = - 8 - ( - 9 )
14 – x + 7 = 1
21 – x = 1
X = 21 – 1
X = 20
22 ) 15 - ( x - 2 ) = - 7 + 8
15 – x + 2 = 1
17 – x = 1
X = 17 – 1
X = 16
6) x + ( - 71 ) = ( - 55 ) + 85
X – 71 = 30
X = 30 + 71
X = 101
7 ) x - ( - 45 ) = - 63 + 27
X +45 = -16
X = -16 -45
X = - 61
6) x + ( - 71 ) = ( - 55 ) + 85
X=30+71=101
7 ) x - ( - 45 ) = - 63 + 27
X=-36-45=-81
8) x + 29 = 43 + ( - 23 )
X=20-29=-9
9 ) x + ( - 47 ) = ( - 62 ) – 17
X=-79+47=-32
10 ) x + 21 = ( - 43 ) + 43
X=0-21=-21
11 ) 31 + x = 45 – 81
X=-36-31=-67
12 ) x - 12 = ( - 8 ) + (- 7 )
X=-15+12=-3
13 ) 23 - x = 24 - ( - 16 )
X=23-40=-17
14 ) - 15 - ( - 21 - 3x ) = - 63 -15+21+3x=-63 21+3x=-63-(-15)
21+3x=-48
3x=-48-21
3x=-69
X=-69 : 3
X=-23
tính bằng cách thuận tiện nhất:
a,7/4 x 11/21 + 11/21 x 5/4
b,23/14 x 6/13 -9/14 x 6/13
a, = \(\frac{11}{21}\)x \(\left(\frac{7}{4}+\frac{5}{4}\right)\)
= \(\frac{11}{21}\)x 3
= \(\frac{33}{21}\)
b) = \(\left(\frac{23}{14}-\frac{9}{14}\right)\)x \(\frac{6}{13}\)
= 1 x \(\frac{6}{13}\)
= \(\frac{6}{13}\)
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Tính
a, -(-5)-(+7)+(+3)+(-8)
b, -(-15)-|-10|+|-9|-|5|
c, 14-(-13)-(17)+(-12)
d, -|-14| + |-10| - (-12) + (-8)
e, -(-11) + (-15) + (13) - 21
Bài 2 tìm x
1, -x + 20 = - (-15) - (8) + 13
2, -(-10) + x = -13 + (-9) + (-6)
3, 8-(-12) + 10 = - (-14) - x
4. - (+12) + (-x) - (-3) = 5 - (-7)
5. 14 - x + (-10) = - (-9) + (+15)
6. 12 - (-17) + (-3) = -5 + x
7. X - (-19) - (+32) = 14 - (+16)
8. X - |-15| - |7| = - (-9) + |-5|
9. 15 - x + 17 = 13 - (-21)
10. - |-5| - (-x) +4 = 3 - (-25)
Mọi NGƯỜI GIẢI GIÚP MÌNH VỚI MK CẦN GẤP, MỌI NGƯỜI GHI RÕ CÁCH LÀM RA NHÉ! CẢM ƠN MỌI NGƯỜI
Bạn ơi bạn làm đc bao nhiêu thì làm phụ mình nhé
bài1
a,
5 - 7 + 3 +(-8)
= -2 + 3 + ( - 8)
= 1 + (-8)= -7
a; - (-5) - (+7) + (+3) + (-8)
= 5 - 7 + 3 - 8
= (5 + 3 - 8) - 7
= (8 - 8) - 7
= 0 - 7
= - 7
1,x/7 x 4/9 x 5 = 3x4x5/7x9
2, tích của 2 phân số tối giản có tử số khác 1 = 6/35 . Tìm tổng của 2 phân số ?
3, tính = cách thuận tiện nhất
a, 6/7 x 16/15 x 7/6 x 21/32 =.....................................
b, 21/17 x 13/14 x 56 x 3/42 =.................................
c, 7/4 x 11/21 + 11/21 x 5/4 =...........................
d, 23/14 x 6/13 - 9/14 x 6/13 =.............................
Bài 1 : Tìm y:
a) y - ( -42 - 2y ) = ( -12 ) - 14 + 2y
b) 15 - ( - y + 5 ) - 5y = - ( 12+ 5y)
c) 2y - ( -5 + 8y - 21 ) = -3 - ( 5y + 2 )
e) - 13 - ( - 3y - 23 ) = - ( 120 - y )
g) - 21 - ( -32 - 5y ) = - ( - 16 - 4y )
Bài 2 :
a) ( - 5 ) x 6 + 15 x 6
b) 9 x ( - 3 ) + 9 x 23
c) ( -10) x 11 + 210 x 11
d) 125 x 4 - 125 x (-4)
a) => y+42+2y= -12-14+2y
y+2y-2y = -12-14-42
y= -68
b) => 15+y-5-5y= -12-5y
y-5y+5y= -12-15+5
y = -22
c) => 2y+5-8y+21= -3-5y-2
2y-8y+5y= -3-2-5-21
-y= -31=>y=31
d)=> -13+3y+23= -120+y
3y-y= -120+13-23
2y= -130=>y= -65
e) => -21+32+5y= 16+4y
5y-4y= 16+21-32
y= 5
bài 1
a)y-(-42-2y) = (-12) - 14 +2y
y +42 + 2y = -12 -14 +2y
3y + 42 = -26 +2y
y = -68
b)15-(-y+5)-5y=-(12+5y+2)
15+y-5-5y=-12-5y-2
10-4y=-14-5y
-4y+5y=-14-10=-24
c)2y-(-5+8y-21)=-3-(5y+2)
2y+5-8y+21=-3y-5y-2
-6y+26=-8y-2
-6y+8y=-2-26
2y=-28
y=-28/2=-14
tinh gia tri bieu thuc:
A) 1000000 - 107492 : 154 x 28 + 1000
B) 8/15 + 4/7 + 14/30 + 12/21 + 5
C) 9/13 : 6/11 - 5/12 : 6/11
Tim x :
1) X x2 + X x 1/5 = 8/5
2) X : 3/8 = 4/3 : 3/6
A) 1000000 - 107492 : 154 x 28 + 1000
= 1000000 - 19544 + 1000
= 981456
B) 8/15 + 4/7 + 14/30 + 12/21 + 5
= 15/7 + 5
= 50/7
C) 9/13 : 6/11 - 5/12 : 6/11
= 9/13 x 11/6 - 5/12 x 11/6
= (9/13 - 5/12) x 11/6
= 43/156 x 11/6
= 473/936
Bài 2
1) X x2 + X x 1/5 = 8/5
X x (2 + 1/5 ) = 8/5
X x 11/5 = 8/5
X = 8/5 x 5/11
X = 8/11
2) X : 3/8 = 4/3 : 3/6
X : 3/8 = 8/3
X = 8/3 x 3/8
X = 1
a) 1 000 000 - 107 492 : 154 x 28 + 1000
= 1 000 000 - 698 x 28 + 1000
= 1 000 000 - 19544 + 1000
= 980 456 + 1000
= 981 456
b) 8/15 + 4/7 + 14/30 + 12/21 + 5
= ( 8/15 + 14/30 ) + ( 4/7 + 12/21 ) + 5
= ( 16/30 + 14/30 ) + ( 12/21 + 12/21 ) + 5
= 30/30 + 24/21 + 5
= 1 + 24/21 + 5
= ( 1 + 5 ) + 24/21
= 6 + 24/21
= 150/21
= 50/7
Bài 1: Tính giá trị của biểu thức sau:
1)2763 + 152 2)(-7) + (-14)
3)(-35) + (-9) 4)(-5) + (-248)
5)(-23) + 105 6)78 + (-123)
7)23 + (-13) 8)(-23) + 13
9)26 + (-6) 10) (-75) + 50
11)80 + (-220) 12) (-23) + (-13)
13)(-26) + (-6) 14 (-75) + (-50)
15)-18 + (-12) 16)17 + -33
17)(– 20) + -88 18) -3 + 5
19)-37 + 15 20)-37 + (-15)
21)(--32) + 5 22)(--22)+ (-16)
23)(-23) + 13 + ( - 17) + 57 24)14 + 6 + (-9) + (-14)
25) (-123) +-13+ (-7) 26) 0+45+(--455)+-796
Bài 2: Bỏ dấu ngoặc rồi tính:
1) (15 + 37) + (52 – 37 – 17) 2) (38 – 42 + 14) – (25 – 27 – 15) 3) –(21 – 32) – (–12 + 32)
4) –(12 + 21 – 23) – (23 – 21 + 10) 5) (57 - 725) - (605 – 53) 6) (55 + 45 + 15) – (15 - 55 + 45)
7)(35 + 75) + (345 – 35 -75) 8) (2002 – 79 + 15) – (-79 + 15)
9)– (515 – 80 + 91) – (2003 + 80 - 91) 10) 25 – (–17) + 24 – 12 11) 235 – (34 + 135) – 100
12/ ( 13 + 49) – ( 13 – 135 + 49) 13/ ( 18 + 29) + ( 158 – 18 – 29)
Bài 3 )Tính các tổng sau một cách hợp lí:
1) (-37) + 14 + 26 + 37 2/ (-24) + 6 + 10 + 24 3) 15 + 23 + (-25) + (-23)
4) 60 + 33 + (-50) + (-33) 5) (-16) + (-209) + (-14) + 209 6) (-12) + (-13) + 36 + (-11)
7) -16 + 24 + 16 – 34 8) 25 + 37 – 48 – 25 – 37 9)2575 + 37 – 2576 – 29
10)* 34 + 35 + 36 + 37 – 14 – 15 – 16 – 17 11)* 4573 + 46 – 4573 + 35 – 16 – 5
12)*32 + 34 + 36 + 38 – 10 – 12 – 14 – 16 – 18
Bài 4: Tìm x Z:
a) a) -7 < x < -1 b) -3 < x < 3 c) -1 ≤ x ≤ 6 d)-5 ≤ x < 6
Bài 5: Tìm tổng của tất cả các số nguyên thỏa mãn:
1/ -4 < x < 3 2/ -5 < x < 5 3/ -10 < x < 6 4/ -6 < x < 5 5/ -5 < x < 2
6/ -6 < x < 0 7/ -1 ≤ x ≤ 4 8/ -6 < x ≤ 4 9/ -4 < x < 4 10/ x< 4 11/x≤ 4
Bài 6*. Tính tổng:
1/ 1 + (-2) + 3 + (-4) + . . . + 19 + (-20)
2/ 1 – 2 + 3 – 4 + . . . + 99 – 100
3/ 2 – 4 + 6 – 8 + . . . + 48 – 50
4/ – 1 + 3 – 5 + 7 - . . . . + 97 – 99
5) 1 + 2 – 3 – 4 + . . . . + 97 + 98 – 99 - 100
Bài 7 : Cho 3;10xy Tính x + y
Bài 8**
a) Chứng minh: A = 2 1 + 2 2 + 2 3 + 2 4 + … + 2 2010 chia hết cho 3; và 7.
b) Chứng minh: B = 3 1 + 3 2 + 3 3 + 3 4 + … + 2 2010 chia hết cho 4 và 13.
c) Chứng minh: C = 5 1 + 5 2 + 5 3 + 5 4 + … + 5 2010 chia hết cho 6 và 31.
d) Chứng minh: D = 7 1 + 7 2 + 7 3 + 7 4 + … + 7 2010 chia hết cho 8 và 57.
Bài 1:
5; (-23) + 105
= 105 - 23
= 82
6; 78 + (-123)
= 78 - 123
= - (123 - 78)
= - 45
bài1
1)2763 + 152 = 2915
2)-7 +(-14)
=-(14 +7)
=-21
Bài 1;
7; 23 + (-13)
= 23 - 13
= 10
8; -23 + 13
- (23 - 13)
= -10
1) tim x biết:
a) (19.x +2.5^2) : 14=(13-8)^2 - 4^2
b) 2.3^x=10.3^12+8.27^4
2) so sanh
a) 5^23 va 6.5^22
b)21^15 va 27^5.49^8
c)3^39 va 11^21
d) 7.2^13 va 2^16