a) 565 - 13.x = 370

13.x = 565 - 370

13.x = 195

x = 195 : 13

x = 15

b) 105 - (135 - 7x) : 9 = 97

(135 - 7x) : 9 = 105 - 97

(135 - 7x) : 9 = 8

135 - 7x = 8 x 9

135 - 7x = 72

7x = 135 - 72

7x = 63

x = 63 : 7

x = 9

a) 565 - 13.x = 370

13.x = 565 - 370

13.x = 195

x = 195 : 13

x = 15

b) 105 - (135 - 7x) : 9 = 97

(135 - 7x) : 9 = 105 - 97

(135 - 7x) : 9 = 8

135 - 7x = 8 x 9

135 - 7x = 72

7x = 135 - 72

7x = 63

x = 63 : 7

x = 9

cho like

\(565-13x=370\\ 13x=565-370=195\\x=\dfrac{195}{13}=15\)

\(105-\left(135-7x\right):9=97\\ \dfrac{135-7x}{9}=105-97=8\\ 135-7x=9.8=72\\ 7x=135-72=63\\ x=\dfrac{63}{7}=9\)

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a, 1260:{x:35}=105
             x:35 = 1260 : 105
             x:35 = 12
             x = 12*35
             x = 420
b, 6885:{135:x}=153
             135:x = 6885:153
             135:x = 45
                   x = 135 : 45
                  x = 3

a) \(4^{x^{ }}=64\)

\(\Rightarrow4^x=4^3\)

\(\Rightarrow x=3.\)

b) Vì \(35⋮x\)

\(\Rightarrow x\inƯ\left(35\right)=\left\{1;5;7;35\right\}\)

Vậy \(x\in\left\{1;5;7;35\right\}\)

c) \(135-\left(x-5\right)=105:3\)

\(\Leftrightarrow\)\(135-\left(x-5\right)=35\)

\(\Leftrightarrow x-5=135-35\)

\(\Leftrightarrow x-5=100\)

\(\Leftrightarrow x=100+5\)

\(\Leftrightarrow\) \(x=105.\)

d) Vì \(x⋮25\)

\(\Rightarrow x\in B\left(25\right)=\left\{0;25;50;75;100;...\right\}\)

Mà \(x< 100\)

\(\Rightarrow x\in\left\{0;25;50;75\right\}\)

a,x/9=5/3 = x=15

b,17/x=85/105 = x = 21

c,6/8=15/x = x =  20

d,x/8=2/3 = x = 6

a: 2x(x+1)-135=-200

=>2(x^2+x)=-65

=>2x^2+2x+65=0

=>x^2+x+32,5=0

=>x^2+x+0,25+32,25=0

=>(x+0,5)^2+32,25=0(vô lý)

b: 4x-5(x-1)+15=13

=>4x-5x+5=-2

=>5-x=-2

=>x=5+2=7

c: 2/3x-1/4=3/5-7/8

=>2/3x=3/5-7/8+1/4=24/40-35/40+10/40=-1/40

=>x=-1/40:2/3=-1/40*3/2=-3/80

d: 1/2(2x-3)+105/2=-137/2

=>1/2(2x-3)=-137/2-105/2=-242/2=-121

=>2x-3=-242

=>2x=-239

=>x=-239/2

=135x (124-23-1)

=135 x 100

=13500

   135 x 124 - 135 x 23 - 135

= 135 x 124 - 135 x 23 - 135 x 1

= 135 x ( 124 - 23 - 1)

= 135 x ( 101 - 1)

= 135 x 100

= 13500

a, 71.2 – 6.(2x+5) =  10 5 : 10 3

71.2 – 6.(2x+5) =  10 2

6.(2x+5) = 71.2 – 100

6.(2x+5) = 42

x = 1

b,  5 x + 3 4 . 6 8 = 6 9 . 3 4

5 x + 3 4 . 6 8 = 6 8 . 6 . 3 4

5 x + 3 4 = 6 8 . 6 . 3 4 : 6 8 = 6 . 3 4

5x =  6 . 3 4 - 3 4 = 5 . 3 4

x =  3 4

c, 12:{390:[5. 10 2  – ( 5 3 + x . 7 2 )]} = 4

390:[5. 10 2  – ( 5 3 + x . 7 2 )] = 12:4 = 3

5. 10 2  – ( 5 3 + x . 7 2 ) = 390:3 = 130

5 3 + x . 7 2 = 5. 10 2  – 130 = 370

x . 7 2 = 370 –  5 3 = 245

x = 245: 7 2 = 5

d,  5 3 .(3x+2):13 =  10 3 : 13 5 : 13 4

5 3 .(3x+2):13 =  10 3 : 13

3x+2 =  10 3 : 13 : 5 3 .13 = 8

x = 2

Đáp án: 135 x 80 + 20 x 135    =   135 x ( 80 + 20 )