T I C K giải cho

A. 150 - 34 + 44 - 66 - 50 = (150 - 50 ) - ( 34 + 66 ) + 44 = 100 - 100 + 44 = 44 

B. 125 - 36 + 25 - 74 = (125 + 25 ) - (36 + 74 ) = 150 - 110 = 40

 a =44 

b = 40

1.

a) \(125+80+375+220\)

\(=\left(125+375\right)+\left(80+220\right)\)

\(=500+300\)

\(=800\)

b) \(25.11.8.4.125\)

\(=\left(25.4\right).\left(8.125\right).11\)

\(=100.1000.11\)

\(=1100000\)

c) \(18.74+18.27-18\)

\(=18.\left(74+27-1\right)\)

\(=18.100\)

\(=1800\)

d) \(75.23+75.77-500\)

\(=75.\left(23+77\right)-500\)

\(=75.100-500\)

\(=7500-500\)

\(=7000\)

e) \(150:\left[25.\left(18-4^2\right)\right]\)

\(=150:\left[25.\left(18-16\right)\right]\)

\(=150:\left[25.2\right]\)

\(=150:50\)

\(=3\)

f) \(125.23.2.8.50\)

\(=\left(125.8\right).\left(2.50\right).23\)

\(=1000.100.23\)

\(=2300000\)

g) \(235+88+165+12\)

\(=\left(235+165\right)+\left(88+12\right)\)

\(=400+100\)

\(=500\)

h) \(71.32+71.68-1100\)

\(=71.\left(32+68\right)-1100\)

\(=71.100-1100\)

\(=7100-1100\)

\(=6000\)

i) \(6^7:6^6+4^3.2-24^0\)

\(=6+64.2-1\)

\(=6+128-1\)

\(=133\)

j) \(546-6.\left[158:\left(30+7^2\right)\right]\)

\(=546-6.\left[158:\left(30+49\right)\right]\)

\(=546-6.\left[158:79\right]\)

\(=546-6.2\)

\(=546-12\)

\(=534\)

k) \(268+147+132+253\)

\(=\left(268+132\right)+\left(147+253\right)\)

\(=400+400\)

\(=800\)

2. 

a) \(7x=707\)

\(x=707:7\)

\(x=101\)

b) \(6x+5=47\)

\(6x=47-5\)

\(6x=42\)

\(x=42:6\)

\(x=7\)

c) \(35:\left(x+1\right)=7\)

\(x+1=35:7\)

\(x+1=5\)

\(x=5-1\)

\(x=4\)

d) \(12+\left(29-3x\right)=35\)

\(29-3x=35-12\)

\(29-3x=23\)

\(3x=29-23\)

\(3x=6\)

\(x=6:3\)

\(x=2\)

e) \(2.4^x+10^1=138\)

\(2.4^x=138-10\)

\(2.4^x=128\)

\(4^x=128:2\)

\(4^x=64=4^3\)

\(\Rightarrow x=3\)

f) \(7x=140\)

\(x=140:7\)

\(x=20\)

g) \(7\left(15-x\right)+14=84\)

\(7\left(15-x\right)=84-14\)

\(7\left(15-x\right)=70\)

\(15-x=70:7\)

\(15-x=10\)

\(x=15-10\)

\(x=5\)

h) \(3^x.5-15=390\)

\(3^x.5=390+15\)

\(3^x.5=405\)

\(3^x=405:5\)

\(3^x=81=3^4\)

\(\Rightarrow x=4\)

3.

Ta có:

\(\Rightarrow n+11⋮n+1\)

\(\Rightarrow n+1+10⋮n+1\)

\(\Rightarrow10⋮n+1\) hay \(n+1\inƯ\left(10\right)=\left\{-10;-5;-2;-1;1;2;5;10\right\}\)

\(\Rightarrow\) \(n\in\left\{-11;-6;-3;-2;0;1;4;9\right\}\)

Vì \(n\in N\) nên \(n\in\left\{0;1;4;9\right\}\)

(45+75)*66+(75+45)*34

=(45+75)*(66+34)

=120*100

=12000

11+22+33+44+55+66+77+88+99:11

=11+22+33+44+55+66+77+88+9

=(11+9)+(22+88)+(33+77)+(44+66)+55

=20+110*3+55

=20+330+55

=405

Ta có :

a, (45 + 75) x 66 + (75 + 45) x 34

=  (45 + 75) x (66 + 34)

=   120  x 100

=  12000

11 + 22 + 33 + 44 + 55 + 66 + 77 + 88 + 99 : 11

= 33 + 77 + 121 + 165 + 9

= 405

\(11+22+33+44+55+66+77+88+99:11\)

\(\left(11+99\right)+\left(22+88\right)+\left(33+77\right)+\left(44+66\right)+55:11\)

\(110+110+110+110+55:11\)

\(440+55:11\)

\(445\)

a) \(48.19+48.15+134.52\)

\(=48\left(19+15\right)+6968\)

\(=48.34+6968\)

\(=1632+6968\)

\(=8600.\)

b) \(27.121-87.27+73.34\)

\(=27\left(121-87\right)+73.34\)

\(=27.34+73.34\)

\(=34\left(27+73\right)\)

\(=34.100\)

\(=3400.\)

c) \(125.98-125.46-52-25\)

\(=125\left(98-46\right)-52-25\)

\(=125.52-52-25\)

\(=52\left(125-1\right)-25\)

\(=52.124-25\)

\(=6448-25\)

\(=6423.\)

d) \(136.23+136.17-40.36\)

\(=136\left(23+17\right)-40.36\)

\(=136.40-40.36\)

\(=40\left(136-36\right)\)

\(=40.100\)

\(=4000.\)

e) \(66.25+5.66+66.14+33.94\)

\(=33\left(2.50+5.2+14.2+94\right)\)

\(=33\left(50+10+28+94\right)\)

\(=33.182\)

\(=6006.\)

Bài 2:

a: \(17-x=3\)

=>\(x=17-3\)

=>x=14(nhận)

b: \(2\cdot\left(x-1\right):3=6\)

=>\(2\left(x-1\right)=6\cdot3=18\)

=>x-1=18/2=9

=>x=9+1=10(nhận)

c: \(x+\left(-2\right)=\left(-11\right)+7\)

=>\(x-2=-4\)

=>\(x=-4+2=-2\left(loại\right)\)

d: \(\left(x-1\right)^2-5=20\)

=>\(\left(x-1\right)^2=25\)

=>\(\left[{}\begin{matrix}x-1=5\\x-1=-5\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=6\left(nhận\right)\\x=-4\left(loại\right)\end{matrix}\right.\)

Câu 3:

a: Đặt *=a

\(\overline{57a3}⋮9\)

=>\(5+7+a+3⋮9\)

=>\(a+15⋮3\)

mà 0<=a<=9

nên a=3

=>*=a

b: \(A=123\cdot7+8+9\)

123*7 là số lẻ

9 là số lẻ

=>123*7+9 chia hết cho 2

mà 8 chia hết cho 2

nên \(A=123\cdot7+9+8⋮2\)

\(123\cdot7⋮3;9⋮3;8⋮̸3\)

=>\(A=123\cdot7+9+8⋮̸3\)

c: \(B=3\cdot5\cdot7+10^{50}\)

\(=5\cdot3\cdot7+5\cdot5^{49}\cdot2^{49}\)

\(=5\left(3\cdot7+5^{49}\cdot2^{49}\right)⋮5\)

=>B là hợp số

con chóa này

. là dấu nhân
\(58.75+58.50.25\)
\(=58.75+58.1250\)
\(=58.\left(75+1250\right)\)
\(=58.1325=76850\)

= 52 nha em

a, = 996 + 4 + 40 = 1000 + 40 = 1040

b, = 198 + 2 + 35 = 200 + 35 = 235

c, = ( 4 *25 )*(2 * 5)*55=100 * 10 * 55 = 55000

d, = 97*(36+64) = 97 * 100 = 9700

e, = (125+75)+(360+40)= 200 + 400 = 600

g, =10^2=100

a) \(996+44\)

    \(=1040\)

b) \(37+198\)

     \(=230\)

\(a,996+44=1040\)                                                                 

\(d,97.36+64.97=97.\left(36+64\right)=97.100=9700\)

\(b,37+198=235\)

\(c,4.55.25.2.5=220.50.5=11000.5=55000\)

\(e,125+360+75+40=485+115=600\)

\(g,10^{12}:10^{10}=10^2=100\)

a: =17+100

=117