1Tính Nhanh
A; 2 x 31 x 12 x 4 + 6x 42+8 x 27x 3
B; 36 x 28 +36 x 82 + 64 x 69 + 64 x 41
tính nhanh
a,65x3,47+3,47x65
a)\(65.3,47+3,47.65\)
\(=65.\left(3,47+3,47\right)\)
\(=65.6,94\)
\(=451,1\)
\(65\times\left(3,47+3,47\right)=65\times6,94=451,1\)
Tính Nhanh
a) 78 . 82
b) 452 + 552 + 90.55
a: \(78\cdot82=80^2-4=6400-4=6396\)
b: \(45^2+90\cdot55+55^2=100^2=10000\)
Tính nhanh
a,30x25x7x8
b,75x8x12x14
Giải chi tiết ạ
`30 xx 25 xx 7 xx8`
`=(30 xx7) xx (25xx8)`
`=210 xx200`
`=42000`
`----`
`75 xx 8 xx 12 xx 14`
`=(75xx8) xx(12xx14)`
`=600xx168`
`=100800`
\(a.30\times25\times7\times8=\left(30\times7\right)\times\left(25\times8\right)=210\times200=42000\)
\(b.75\times8\times12\times14=\left(75\times12\right)\times\left(8\times14\right)=900\times112=100800\)
\(a,30.25.7.8\\ =\left(30.7\right).\left(25.8\right)\\ =210.200\\ =42000\\ b,75.8.12.14\\ =\left(75.12\right).\left(8.14\right)\\ =900.112\\ =100800\)
P(x)+P(1/x)=2x-1
tính P(2022)
P(2)+P(1/2)=2*2-1=3
P(1/2)+P(2)=2*1/2-1=1
=>Ko tồn tại P(x) thỏa mãn đièu kiện
1.Tính nhanh
a, A=8,95*90+89+50%
=8,95*90+89,5
=89,5(9+1)
=895
1. Tính nhanh
a) (-0,4)x(-0,5)x(-0,8)
Tính nhanh
a) 34,5 x 5,789 + 0,4211 x 345
=34,5x5,789+4,211x34,5
=34,5x(5,789+4,211)
=34,5x10
=345
cho x+y =1
Tính A= x\(^3\) + 3xy +y\(^3\)
Ta có:
\(x+y=1\)
\(\Rightarrow\left(x+y\right)^3=1^3\)
\(\Rightarrow\left(x+y\right)^3=1\)
\(\Rightarrow x^3+3x^2y+3xy^2+y^3=1\)
\(\Rightarrow x^3+3xy\left(x+y\right)+y^3=1\)
\(\Rightarrow x^3+3xy\cdot1+y^3=1\)
\(\Rightarrow x^3+3xy+y^3=1\)
Vậy: \(x^3+3xy+y^3=1\)
Tính nhanh
a, 68\(^2\)+64.68+32\(^2\)
b, 51.49
a: \(68^2+64\cdot68+32^2\)
\(=\left(68+32\right)^2\)
=10000
b: \(51\cdot49=50^2-1=2499\)
tính nhanh
a 20,11x 7,5 +20,11+20,11
20,11x05
b 2,5 x 12,85x4
a: \(20,11\cdot7,5+20,11+20,11+20,11\cdot0,5\)
\(=20,11\left(7,5+1+1+0,5\right)\)
\(=20,11\cdot10=201,1\)
b: \(2,5\cdot12,85\cdot4\)
\(=12,85\cdot\left(2,5\cdot4\right)\)
\(=12,85\cdot10=128,5\)
a: 20,11⋅7,5+20,11+20,11+20,11⋅0,520,11⋅7,5+20,11+20,11+20,11⋅0,5
=20,11(7,5+1+1+0,5)=20,11(7,5+1+1+0,5)
=20,11⋅10=201,1=20,11⋅10=201,1
b: 2,5⋅12,85⋅42,5⋅12,85⋅4
=12,85⋅(2,5⋅4)=12,85⋅(2,5⋅4)
=12,85⋅10=128,5
a: 20,11⋅7,5+20,11+20,11+20,11⋅0,520,11⋅7,5+20,11+20,11+20,11⋅0,5
=20,11(7,5+1+1+0,5)=20,11(7,5+1+1+0,5)
=20,11⋅10=201,1=20,11⋅10=201,1
b: 2,5⋅12,85⋅42,5⋅12,85⋅4
=12,85⋅(2,5⋅4)=12,85⋅(2,5⋅4)
=12,85⋅10=128,5=12,85⋅10=128,5