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1: =-3x5+2x5-7x5+7x4=-8x5+7x4=-40+28=-12
2: =-3x5+3x6-4x3+4x2=-9+8=-1
3: =17(-84-16)=-1700
4: =1975(-115+15)=-197500
5: =-145x13+145x57+57x10-57x145=-1315
1/ \(5\left(-3+2\right)-7\left(5-4\right)\)
\(=5.\left(-3\right)+5.2-7.5-7.\left(-4\right)\)
\(=-15+10-35+28\)
\(=-5-7\)
\(=-12\)
2/ \(3.\left(-5+6\right)-4.\left(3-2\right)\)
\(=3.\left(-5\right)+3.6-4.3-4.\left(-2\right)\)
\(=-15+18-12+8\)
\(=3-4\)
\(=-1\)
3/ \(17.\left(-84\right)+17.\left(-16\right)\)
\(=17.\left(-84-16\right)\)
\(=17.\left(-100\right)\)
\(=-1700\)
4/ \(1975.\left(-115\right)+1975.15\)
\(=1975.\left(-115+15\right)\)
\(=1975.\left(-100\right)\)
\(=-197500\)
5/ \(-145.\left(13-57\right)+57.\left(10-145\right)\)
\(=-145.13-145.\left(-57\right)+57.10+57.\left(-145\right)\)
\(=-145.\left(-57+57\right)-145.13+57.10\)
\(=0-1885+570\)
\(=-1315\)
6/ \(157.17-157.7\)
\(=157.\left(17-7\right)\)
\(=157.10\)
\(=1570\)
7/ \(199.\left(15-17\right)-199.\left(-17+5\right)\)
\(=199.\left(-2\right)-199.\left(-12\right)\)
\(=199.\left(-2\right)+199.12\)
\(=199.\left(-2+12\right)\)
\(=199.10\)
\(=1990\)
8/ \(-39.\left(5-99\right)+99.\left(10-39\right)\)
\(=-39.5-39.\left(-99\right)+99.10+99.\left(-39\right)\)
\(=-39.\left(-99+99\right)-39.5+99.10\)
\(=0-195+990\)
\(=795\)
9/ \(-38.\left(25-4\right)+25.\left(-4+38\right)\)
\(=-38.25-38.\left(-4\right)+25.\left(-4\right)+25.38\)
\(=25.\left(-38+38\right)-4.\left(-38+25\right)\)
\(=0-4.\left(-13\right)\)
\(=52\)
10/ \(\left(-37\right).86+37.76\)
\(=37.\left(-86\right)+37.76\)
\(=37.\left(-86+76\right)\)
\(=37.\left(-10\right)\)
\(=-370\)
2) -3(4 - 7) + 5(-3 + 2)
= -3.4 + 3.7 - 5.3 + 5.2
= -12 + 21 -15 + 10
= 31 - 27
= 4
4) -5(2 - 7) + 4(2 - 5)
= -5.2 + 5.7 + 4.2 - 4.5
= -10 + 35 + 8 - 20
= 38 - 30
= 8
3: \(=20-12-8+12=20-8=12\)
5: \(=-18-42-21-35=-116\)
3: \(=-15+18-12+8=-27+26=-1\)
2: \(=-12+21-15+10=9-5=4\)
a, 7\(x\) - \(x\) = 521 : 519 + 3.22.7
6\(x\) = 53 + 3.4.7
6\(x\) = 125 + 12.7
6\(x\) = 125 + 84
6\(x\) = 209
\(x\) = 209 : 6
\(x\) = \(\dfrac{209}{6}\)
b; 11\(x\) - 7\(x\) + 34 : 33 = 54 + 2\(x\)
4\(x\) + 3 = 625 + 2\(x\)
4\(x\) - 2\(x\) = 625 - 3
2\(x\) = 622
\(x\) = 622 : 2
\(x\) = 311
c; 75 - 5.(\(x-3\))3 = 700
5.(\(x\) - 3)3 = 700 - 75
5.(\(x\) - 3)3 = - 625
(\(x\) - 30)3 = - 625 : 5
(\(x\) - 30)3 = - 125
(\(x-3\))3 = (-5)3
\(x\) - 3 = - 5
\(x\) = - 5 + 3
\(x\) = -2
d, 3.(2\(x\) - 1)2 = 75
(2\(x\) - 1)2 = 75 : 3
(2\(x\) - 1)2 = 25
\(\left[{}\begin{matrix}2x-1=-5\\2x-1=5\end{matrix}\right.\)
\(\left[{}\begin{matrix}2x=-5+1\\2x=5+1\end{matrix}\right.\)
\(\left[{}\begin{matrix}2x=-4\\2x=6\end{matrix}\right.\)
\(\left[{}\begin{matrix}x=-2\\x=3\end{matrix}\right.\)
a)
\(\begin{array}{l}\frac{2}{3} + \frac{{ - 2}}{5} + \frac{{ - 5}}{6} - \frac{{13}}{{10}}\\ = \frac{2}{3} + \frac{{ - 5}}{6} + \frac{{ - 2}}{5} - \frac{{13}}{{10}}\\ = \left( {\frac{2}{3} + \frac{{ - 5}}{6}} \right) + \left( {\frac{{ - 2}}{5} - \frac{{13}}{{10}}} \right)\\ = \left( {\frac{4}{6} + \frac{{ - 5}}{6}} \right) + \left( {\frac{{ - 4}}{{10}} - \frac{{13}}{{10}}} \right)\\ = \frac{{ - 1}}{6} + \frac{{ - 17}}{{10}}\\ = \frac{{ - 5}}{{30}} + \frac{{ - 51}}{{30}}\\ = \frac{{ - 56}}{{30}}\\ = \frac{{ - 28}}{{15}}\end{array}\)
b)
\(\begin{array}{l}\frac{{ - 3}}{7}.\frac{{ - 1}}{9} + \frac{7}{{ - 18}}.\frac{{ - 3}}{7} + \frac{5}{6}.\frac{{ - 3}}{7}\\ = \frac{{ - 3}}{7}.\left( {\frac{{ - 1}}{9} + \frac{7}{{ - 18}} + \frac{5}{6}} \right)\\ = \frac{{ - 3}}{7}.\left( {\frac{{ - 2}}{{18}} + \frac{{ - 7}}{{18}} + \frac{{15}}{{18}}} \right)\\ = \frac{{ - 3}}{7}.\frac{{ 6}}{{18}}\\ = \frac{-1}{7}\end{array}\).
\(2^3.2^2+5^5:5^3\)
\(=2^5+5^2\)
\(=32+25\)
\(=57\)
Bài 1 a, \(17.25\)
\(=\left(1+16\right).25\)
\(=1.25+16.25\)
\(=25+4.4.25\)
\(=25+4.100\)
\(=25+400\)
\(=425\)
b, Bạn kia làm rồi nhé!
c, \(29.31+66.69+31.37\)
\(=31.\left(29+37\right)+66.99\)
\(=31.66+66.69\)
\(=66\left(31+69\right)\)
\(=66.100\)
\(6600\)