Tìm x
(-7).x=-37+79
Tìm X biết: 79 – (X – 18) = 37
79 - (x - 18) = 37
x - 18 = 79 - 37
x - 18 = 42
x = 42 + 18
x = 60
79 - ( x-18 ) = 37
x-18 = 79 - 37
x-18 = 42
x = 42 + 18
x = 60
Tìm x
79 - ( x - 18 ) = 37
79 - (x - 18) = 37
=> x - 18 = 79 - 37
x - 18 = 42
=> x = 42 + 18
x = 60
Bài 2 : Tính nhanh
a ) ( 8 , 7 x 29 + 8, 7 x 35 ) : 64
b ) 372 x 9 + 372
c ) 37 x 24 + 37 x 76 + 63 x 79 + 63 x 21
d ) 42 x 53 + 47 x 156 - 47 x 114
giúp mk nha . Làm ơn nhanh lên nhé
Thannks
Bài 2 : Tính nhanh
a ) ( 8 , 7 x 29 + 8, 7 x 35 ) : 64
= [ 8.7 x ( 29 + 35 ) ] : 64
= [ 8.7 x 64 ] : 64
= 8.7
b ) 372 x 9 + 372
= 372 x ( 9 + 1 )
= 372 x 10
= 3720
c ) 37 x 24 + 37 x 76 + 63 x 79 + 63 x 21
= 37 x ( 24 + 76 ) + 63 x ( 79 + 21 )
= 37 x 100 + 63 x 100
= 100 x ( 37 + 63 )
= 100 x 100
= 10000
d ) 42 x 53 + 47 x 156 - 47 x 114
= 42 x 53 + 47 x ( 156 - 114 )
= 42 x 53 + 47 x 42
= 42 x ( 53 + 47 )
= 42 x 100
= 4200
hok tốt nha
a) (8,7 x 29 + 8,7 x 35) : 64
= [8,7 x (29 + 35)] : 64
= (8,7 x 64) : 64
= 8,7 x (64 : 64)
= 8,7 x 1 = 8,7
b) 372 x 9 + 372 = 372 x (9 + 1)
= 372 x 10 = 3720
c) 37 x 24 + 37 x 76 + 63 x 79 + 63 x 21
= 37 x (24 + 76) + 63 x (79 + 21)
= 37 x 100 + 63 x 100
= (37 + 63) x 100
= 100 x 100 = 10000
d) 42 x 53 + 47 x 156 - 47 x 114
= 42 x 53 + 47 x (156 - 114)
= 42 x 53 + 47 x 42
= 42 x (53 + 47)
= 42 x 100
= 4200
a ) ( 8 , 7 x 29 + 8, 7 x 35 ) : 64
= [ 8,7 x ( 29 + 35 ) ] : 64
= 8,7 x 64 : 64
= 8,7
b ) 372 x 9 + 372
= 372 x ( 9 + 1 )
= 372 x 10
= 3720
c ) 37 x 24 + 37 x 76 + 63 x 79 + 63 x 21
= [ 37 x ( 24 + 76 ) ] + [ 63 x ( 79 + 21 ) ]
= [ 37 . 100 ] + [ 63 x 100 ]
= 3700 + 6300
= 10000
d ) 42 x 53 + 47 x 156 - 47 x 114
= 42 x 53 + 47 x ( 156 - 114 )
= 42 x 53 + 47 x 42
= 42 x ( 53 + 47 )
= 42 x 100
= 4200
Bai 1 : Tinh a) 24 - (-15) - 2 b) (-85) + 10 - (-85) - 50 c) 71 - (-30) - (+18) + (-30)
d) -(30) - (+37) + (+37) + (-85) e) (35-815) - (795-65) g) (2002-79+15) + (-79+15)
h) -(515-80+91) - (2003+80-91)
Bai 2: Tim x,biet a) 25 - (30+x) = x - (27-8) b) (x-12) - 15 = (20-17) - (18+x) c) 15 - x = 7 - (-2) d) x - 35 = (-12) - 3 e) I5-xI - 26 = - 15
Bài 1:
a) \(24 - (-15) - 2\)
\(=39-2\)
\(=37\)
b) \((-85) + 10 - (-85) - 50\)
\(=[(-85)-(-85)]+10-50\)
\(=0+10-50\)
\(=10-50\)
\(=-40\)
c) \(71 - (-30) - (+18) + (-30)\)
\(=[(-30)-(-30)]+71-(+18)\)
\(=0+71-18\)
\(=71-18\)
\(=53\)
d) \(-(30) - (+37) + (+37) + (-85)\)
\(=[-(+37)+(+37)]-(30)+(-85)\)
\(=0-(30)+(-85)\)
\(=(-30)+(-85)\)
\(=-115\)
e) \((35-815) - (795-65)\)
\(=(-780)-730\)
\(=-1510\)
g) \((2002-79+15) + (-79+15)\)
\(=1938+(-64)\)
\(=1874\)
Bài 2:
a) \(25 - (30+x) = x - (27-8)\)
\(25-30-x=x-27+8\)
\(x+x=25-30+27-8\)
\(2x=14\)
\(x=14\div2\)
\(x=7\)
b) \((x-12) - 15 = (20-17) - (18+x) \)
\(x-12-15=13-18-x\)
\(x-27=-5-x\)
\(x+x=-5+27\)
\(2x=22\)
\(x=22\div2\)
\(x=11\)
c) \(15 - x = 7 - (-2)\)
\(15-x=9\)
\(x=15-9\)
\(x=6\)
d) \(x - 35 = (-12) - 3\)
\(x-35=-15\)
\(x=-15+35\)
\(x=20\)
e) \(\left|5-x\right|-26=-15\)
\(\left|5-x\right|=-15+26\)
\(\left|5-x\right|=11\)
Từ đây ta có:
*Nếu \(5-x=11\)
\(x=5-11\)
\(x=-6\)
*Nếu \(5-x=-11\)
\(x=5-(-11)\)
\(x=16\)
Vậy \(x=-6;x=16\)
Tìm x:
(x + 3 ) + ( x + 7 ) + ( x + 11 ) + .......... + ( x + 79 ) = 1720
x . 20 + ( 3 + 7 + 11 + ... + 79 ) = 1720
x . 20 + 820 = 1720
x . 20 = 1720 - 820
x . 20 = 900
x = 900 : 20
x = 45
(x + 3 ) + ( x + 7 ) + ( x + 11 ) + .......... + ( x + 79 ) = 1720
x . 20 + ( 3 + 7 + 11 + ... + 79 ) = 1720
x . 20 + 820 = 1720
x . 20 = 1720 - 820
x . 20 = 900
x = 900 : 20
x = 45
(x+3)+(x+7)+(x+11)+...+(x+79)=1720
(x+x+x+.....+x)+(3+7+11+...+79)=1720
x.20+820=1720
x.20=1720-820
x.20=900
x=900:20
x=45
2, Tìm x:
a) 45 + x = 79 + 2x
b) 15 - (x + 7) = (x - 8) +22
c) |x| = 5
d) x - ƯCLN(16; 24) = 7
Bài 2:
a: Ta có: \(2x+79=x+45\)
nên 2x-x=45-79
hay x=-24
b: Ta có: \(15-\left(x+7\right)=\left(x-8\right)+22\)
\(\Leftrightarrow8-x-x-14=0\)
\(\Leftrightarrow2x=22\)
hay x=11
tính nhanh 163^2 + 79 x 163 + 37^2
\(163^2+79.163+37^2=163\left(163+79\right)+37^2=163.242+37^2=5001574\)
BÀI 1: TÌM X
a) ( x^2 + 1 ) - ( x + 1 ) ( x - 1 ) + x - 4 = 0
b) ( x + 2 ) ( x^2 - 2x + 4 ) - x ( x^2 + 2 ) = 30
c) ( x + 4)^2 - ( x + 1 ) ( x - 1 ) = 16
d) ( 2x - 1)^2 + ( x + 3)^2 - 5 ( x + 7 ) ( x - 7 ) = 0
BÀI 2: TÍNH NHANH
a) 201^2
b) 199^2
c) 37 . 43
d) 37^2 + 2 . 37 . 13 + 13^2
đ) 51,7^2 - 2 . 51,7 . 31,7 + 31,7^2
e) 35^2 + 65^2 + 70,65
f) 79^2 + 39^2 - 78 . 79
BÀI 3: viết mỗi biểu thức sau dưới dạng tổng, hiệu 2 bình phương.
a) x^2 + 10x + 26 + y^2 + 2y
b) z^2 - 6z + 5 - t^2 - 4t
c) x^2 - 2xy + 2 y^2 + 2y + 1
d) 4 x^2 - 12x - y^2 + 2y + 1
GIÚP EM VỚI NHA ! EM LÀ DÂN GHA / HĐA NHA <33
Ta có : (x2 + 1) - (x + 1)(x - 1) + x - 4 = 0
<=> (x2 + 1) - (x2 - 1) + x - 4 = 0
<=> x2 + 1 - x2 + 1 + x - 4 = 0
<=> x - 2 = 0
=> x = 2
Tim x
a } 120 - ( x + 14 ) = 45
b } 79 - x- 18 = 37
a) 120 - ( x + 14 ) = 45
x + 14 = 120 - 45
x + 14 = 75
x = 75 - 14
x = 61
b) 79 - x - 18 = 37
79 - x = 37 + 18
79 - x = 55
x = 79 - 55
x = 24
a)120-(x+14)=45
=>x+14=120-45
=>x+14=75
=>x=61
b) tự làm
a,120-(x+14)=45
x+14=120-45
x+14=75
x=75-14
x=61
Vậy...
b,79-x-18=37
79-x=37-18
79-x=19
x=79-19
x=60
Vậy...