42+(3x+7):2= 32+ 81

(3x+7):2= 113-42

3x+7= 71x2

3x= 142-7

x= 135:3

x= 45

mình nha bạn

\(2^{x+5}+2^{x+2}=48\)

\(\Leftrightarrow2^{x+2}\left(2^3+1\right)=48\)

\(\Leftrightarrow9\cdot2^{x+2}=48\)

\(\Leftrightarrow2^{x+2}=\frac{16}{3}\)

Đề có sai ko hả bạn

2^x+5+2^x+2=48

2^2x+7=48

x=5 nếu +9

\(2^{x+5}+2^{x+2}=48\)

\(\Rightarrow2^x.32+2^x.4=48\)

\(\Rightarrow2^x\left(32+4\right)=48\)

\(\Rightarrow2^x.36=48\Rightarrow2^x=48:36=\frac{4}{3}\)

\(.......................................\)

\(\frac{x+5}{48}=\frac{1}{6}\)

\(\frac{x+5}{48}=\frac{8}{48}\)

x+5=8

x=8-5

x=3

* = nhân nhé

( ( x . 32 ) - 17 ) . 2 = 42

( ( x . 32 ) - 17 ) = 42 : 2

( ( x . 32 ) - 17 ) = 21

x . 32 = 21 + 17

x . 32 = 38

x = 38 : 32

x = 19/16

88 - 3 . ( 7 + x ) = 64

3 . ( 7 + x ) = 88 - 64 

3 . ( 7 + x ) = 24

7 + x = 24 : 3 

7 + x = 8

x = 8 - 7

x = 1

7/x=y/27=-42/54=-7/9

7/x=-7/9 nên x=-9

y/27=-7/9=-21/27 nên y=-21

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Ta nhân thì thấy 6 x 7 = 42 . Ta lấy 42 trừ đi 42 bằng 5

6 x 6 = 36       63 : 7 = 9       7 x 5 = 35       6 x 7 = 42

7 x 7 = 49       48 : 6 = 8       35 : 7 = 5       42 : 6 = 7

5 x 5 = 25       49 : 7 = 7       35 : 5 = 7       42 : 7 = 6

6 x 6 = .36....       63 : 7 = 9.....       7 x 5 = .35......    6 x 7 = ..42...

7 x 7 = ..42...       48 : 6 = ..8...       35 : 7 = ...5..       42 : 6 = ..7...

5 x 5 = ...25..       49 : 7 = .7....       35 : 5 = ...7..       42 : 7 = ..6...

hok tốt