a) a=8

b) a=6; b=4; c=2

c) a=3; b=1

\(\left(a\right)\overline{a3}-17=66\)

\(\overline{a3}=66+17=83\)

a = 8

\(\left(b\right)\overline{a42}+\overline{b5}+\overline{10c}=789\)

\(a\cdot100+40+2+b\cdot10+5+100+c=789\)

\(\overline{abc}+147=789\)

\(\overline{abc}=789-147=642\)

a = 6; b = 4; c = 2

\(\left(c\right)\overline{ab}+281=\overline{ab0}+2\)

\(281-2=\overline{ab0}-\overline{ab}\)

\(279=\overline{ab}\cdot9\)

\(\overline{ab}=\frac{279}{9}=31\)

a = 3; b = 1

\(\left(d\right)\overline{2ab2}=\overline{ab}\cdot11+1989\)

\(2002+\overline{ab0}=\overline{ab}\cdot11+1989\)

\(2002-1989=\overline{ab}\cdot11-\overline{ab0}\)

\(\overline{ab}=13\)

a = 1; b = 3

\(\left(e\right)\overline{ab}\cdot6=\overline{a0b}\)

\(\left(a\cdot10+b\right)\cdot6=a\cdot100+b\)

\(a\cdot60+b\cdot6=a\cdot100+b\)

\(b\cdot6-b=a\cdot100-a\cdot60\)

\(b\cdot5=a\cdot40\)

\(b=a\cdot8\)

Suy ra a = 1; b = 8

Cgcr

\(4\Omega6=4+5+6+7+8+9=39\)

khờ thế !

\(77+2\times x=87\)

            \(2\times x=87-77\)

             \(2\times x=10\)

                     \(x=10:2\)

                      \(x=5\)

Vậy \(x=5\)

2xX=87-77

2xX=10

X=10:2

X=5

7 giờ 7 phút >1/4 giò

200 phút>2 giò 19 phút

8 kg 17 g>1/4kg

9km 6hm 8dam=968 dam

Bài: So Sánh

a) 7 giờ 7 phút > 1/4  giờ

b) 200 phút > 2 giờ 19 phút

c) 8 kg 17g > 1/4 kg

d) 9 km 6 hm 8 dam =968 dam

Bài 1 :

a , x = 675

b , x = 1764

c , x = 0

Bài 2 :

a , x = 3 , 2 , 1 , 0

b , x = 6 , 5 , 4 , 3 , 2 , 1 , 0

c , x = 3 , 4

Bài 1:Tìm x

a, x:5=27\(x\)5

    x:5=135

    x  =135\(x\)5

    x  =675

b, x:7=36\(x\)7

    x:7=252

    x  =252\(x\)7

    x  =1764

c,x\(x\)132=312 x (5-3-2)

  x\(x\)132=312x0

x\(x\)132=0

x          =0:132

x          =0

B1

a) 17 b) 6 c) 112 d)9687

B2

100-x=33

x=100-33

x= 67

Ko bít

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