Câu 1:
a) \(35.34+35.86+65.75+65.45\\ =35.\left(34+86\right)+65.\left(75+45\right)\\ =35.120+65.120\\ =\left(35+65\right).120\\ =100.120\\ =12000\)
b) \(21.7^2-11.7^2+90.7^2+49.125.16\\ =\left(21-11+90+125.16\right).7^2\\ =2100.7^2\\ =102900\)
\(a.35.34+35.86+65.75+65.45\)
\(=35.\left(34+86\right)+65.\left(75+45\right)\)
\(=35.120+65.120\)
\(=\left(35+65\right).120\)
\(=100.120\)
\(=12000\)
\(b.21.7^2-11.7^2+90.7^2+49.125.16\)
\(=\left(21-11+90+2000\right)7^2\)
\(=2100.7^2\)
\(=102900\)
a) 35 . 34 + 35 . 86 + 65 . 75 + 65 . 45
= 35 . (34 + 86) + 65 . (75 + 45)
= 35 . 120 + 65 . 120
= (35 + 65) . 120
= 100 . 120 = 12000
b) 21 . 72 - 11 . 72 + 90 . 72 + 49 . 125 . 16
= 21 . 72 - 11 . 72 + 90 . 72 + 72 . 125 . 16
= (21 - 11 + 90 + 125 . 16) . 72
= 2100 . 72
= 2100 . 49 = 102900
a) \(35\cdot34+35\cdot86+65\cdot75+65\cdot45\\ =35\left(34+86\right)+65\left(75+45\right)\\ =35\cdot120+65\cdot120\\ =\left(35+65\right)\cdot120\\ =100\cdot120\\ =12000\)
b) \(21\cdot7^2-11\cdot7^2+90\cdot7^2+49\cdot125\cdot16\\ =21\cdot7^2-11\cdot7^2+90\cdot7^2+7^2\cdot2000\\ =7^2\left(21-11+90+2000\right)\\ =7^2\cdot2100\\ =49\cdot2100\\ =102900\)
\(a.35.34+35.86+65.75+65.45\)
\(35.\left(34+86\right)+65.\left(75+45\right)\)
\(35.120+65.120\)
\(120.\left(65+35\right)\)
\(120.100\)
\(12000\)
\(b.21.7^2-11.7^2+90.7^2+49.125.16\)
\(21.7^2-11.7^2+90.7^2+7^2.125.16\)
\(7^2.\left(21-11+90+2000\right)\)
\(7^2.2100\)
\(102900\)
tick cho mink nha
