\(87^2\)+\(73^2\)-\(27^2\)-\(13^2\)
87^2+73^2-27^2-13^2
87^2+73^2-27^2-13^2
=(87+73-27-13)^2
=120^2
=14400
\(87^2+73^2-27^2-13^2=\left(87^2-27^2\right)+\left(73^2-13^2\right)\)
\(=\left(87-27\right)\left(87+27\right)+\left(73-13\right)\left(73+13\right)\)
\(=60\cdot114+60\cdot86=60\left(114+86\right)=60\cdot200=12000\)
Tính nhanh 872+732-272-132
872+732-272-132
=(872-132)+(732-272)
=(87+13)(87-13)+(73+27)(73-27)
=100.74+100.46
=100.(74+46)
=100.120
=12000
Tính nhanh
872 + 732 - 272 - 132
\(87^2+73^2-27^2-13^2\)
\(=\left(87^2-13^2\right)+\left(73^2-27^2\right)\)
\(=\left(87+13\right)\left(87-13\right)+\left(73-27\right)\left(73+27\right)\)
\(=100.74+100.46\)
\(=100\left(74+46\right)\)
\(=100.120\)
\(=12000\)
Vậy ...
tính nhanh
a, 69 mũ 2 - 31 mũ 2
b, 1023 mũ 2 - 23 mũ 2
c, 27 mũ 2 + 73 mũ 2 + 54.73
d, 63 mũ 2 + 13 mũ 2 - 26 . 63
e, 25 mũ 2 - 15 mũ 2
i, 87 mũ 2 + 73 mũ 2- 27 mũ 2 - 13 mũ 2
a)\(69^2-31^2=\left(69-31\right)\left(69+31\right)=38.100=3800\)
\(1023^2-23^2=\left(1023-23\right)\left(1023+23\right)=1000.1046=1046000\)
\(c,\left(27+73\right)^2-2.27.73+54.73\)
\(100^2-54.73+54.73=10000\)
\(d,\left(63-13\right)^2+2.13.63-26.63=50^2=2500\)
Tính nhanh
1). \(25^2-15^2\)
2). \(87^2+73^2-27^2-13^2\)
Giải:
1). \(25^2-15^2\)
\(=\left(25-15\right)\left(25+15\right)\)
\(=10.40\)
\(=400\)
2). \(87^2+73^2-27^2-13^2\)
\(=\left(87^2-13^2\right)+\left(73^2-27^2\right)\)
\(=\left(87-13\right)\left(87+13\right)+\left(73-27\right)\left(73+27\right)\)
\(=74.100+46.100\)
\(=100\left(74+46\right)\)
\(=100.120\)
\(=12000\)
Chúc bạn học tốt!!!
Tính nhanh :
a) \(25^2-15^2\)
b) \(87^2+73^2-27^2-13^2\)
a) \(25^2-15^2=\left(25-15\right)\left(25+15\right)\)
= 400
b) \(87^2+73^2-27^2-13^2\)
\(\Leftrightarrow\left(87^2-13^2\right)\)+\(\left(73^2-27^2\right)\)
\(\Leftrightarrow\left(87+13\right)\left(87-13\right)+\left(73+27\right)\left(73-27\right)\)
\(\Leftrightarrow7400+4600=12000\)
tính nhanh
a) 252 - 152
b) 872 + 732 - 272 - 132
a) \(25^2-15^2=\left(25-15\right)\left(25+15\right)=10.40=400\)
b) \(87^2+73^2-27^2-12^2\)
\(=\left(87^2-13^2\right)+\left(73^2-27^3\right)\)
\(=\left(87-13\right)\left(87+13\right)+\left(73-27\right)\left(73+27\right)\)
\(=74.100+100.46\)
\(=100\left(74+46\right)\)
\(=100.120=12000\)
tìm x biết x-13/87+x-27/73+x-67/33+x-73/27=|1-4|.2019^0+1
Tính nhẩm:
a) \(26^2+52.24+24^2\)
b) \(3003^2-3^2\)
c) \(87^2+73^2-27^2-13^2\)
d) \(79^2-79.58+29^2\)
a) 262 + 52.24 + 242
= 262 + 2.26.24 + 242
= ( 26 + 24 )2
= 502 = 2500
b) 30032 - 32
= ( 3003 + 3 ) ( 3003 - 3 )
= 3006 . 3000 = 9018000
c) 872 + 732 - 272 -132
= ( 872 - 132 ) + ( 732 - 272 )
= [ ( 87 + 13 )( 87- 13 )] + [ ( 73 - 27 )( 73 + 27 ) ]
= ( 100 . 74 ) + ( 46 . 100 )
= 7400 + 4600 = 12000
d)792 - 79.58 + 292
= 792 - 2.79.29 + 292
= ( 79 - 29 )2
= 502 = 2500
a) 262 + 52 . 24 + 242 = 262 + 2 . 26 . 24 + 242
= ( 26 + 24 )2
= 502
= 2500
b) 30032 - 32 = ( 3003 - 3 ) . ( 3003 + 3 )
= 3000. 3006
= 9018000
c) 872 + 732 - 272 - 132 = ( 872 - 272 ) + ( 732 - 132 )
= ( 87 - 27 ) . ( 87 + 27 ) + ( 73 - 13 ) . ( 73+13)
= 60 . 114 + 60 . 86
= 60 . ( 114 + 86 )
= 60 . 200
= 12000
d) 792 - 79 . 58 + 292 = 792 - 2 . 79 . 29 + 292
= ( 79 - 29 )2
= 502
= 2500