a./ x-15=53

x=53+15

x=68

b./43-x=23

x=43-23

x=20

c./ 23+x=56

x=56-23

x=33

a) x - 15 = 53

=> x = 53 + 15

=> x = 68

b) 43 - x = 23

=> x = 43 - 23

=> x = 20

c) 23 + x = 56

=> x = 56 - 23

=> x = 33

a./ 68

b./20

c./33

Ta có: 23 + 3x = 56 : 53

23 + 3x = 5(6-3)

23 + 3x = 53

23 + 3x = 125

3x = 125 – 23

3x = 102

x = 102 : 3

x = 34

123-76=47

56-51=5

78-56=22

56-7x5=21

53-23=30

42:2=21

chúc bạn học giỏi hơn

tk mình nha

123-76=47     :      56-51=5         : 78-56=22    

56-(7x5)

56-35=21       :      53-23=30       :  42 :2=21

\(123-76=47\)

\(56-51=5\)

\(78-56=22\)

\(56-7\times5=21\)

\(53-23=30\)

\(42:2=41\)

23 . ( 43 - x) = 23

43-x=23:23

43-x=1

x=43-1

x=42

23 . ( 43 - x ) = 23

43 - x            = 23 : 23

43 - x            = 1

x                   = 43 -1

x                   = 42

Vậy x = 42 

Học tốt!!!

23.(43-x)=23

(43-x)=23:23

(43-x)=1

x=43-1

x=42

vậy x=42

\(=5^1+2^5=5+32\\ =37\)

157

\(5^6:5^3+2^3.2^2\)
\(\Rightarrow5^3+2^5\)
\(\Rightarrow125+32\)
\(\Rightarrow157\)

x=4

\(\frac{8}{23}\cdot\frac{46}{24}-x=\frac{1}{3}\)

=> \(\frac{2}{3}-x=\frac{1}{3}\)

=> \(x=\frac{1}{3}\)

\(\frac{10}{12}\div x=\frac{28}{9}\cdot\frac{3}{56}\)

=> \(\frac{10}{12}\div x=\frac{1}{6}\)

=> \(x=\frac{60}{12}=5\)

\(\frac{x-12}{4}=\frac{1}{2}\)

=> \(\left(x-12\right)\cdot2=4\cdot1\)

=> \(2x-24=4\)

=> \(2x=28\)

=> \(x=14\)

\(a,\left(x+3\right)\left(5-x\right)=0\\ \Rightarrow\left\{{}\begin{matrix}x+3=0\\5-x=0\end{matrix}\right.\Rightarrow\left\{{}\begin{matrix}x=-3\\x=5\end{matrix}\right.\)

\(c,x+17⋮x+3\\ x+3+14⋮x+3\\ 14⋮x+3\\ x+3\inƯ\left(14\right)=\left\{\pm14;\pm7\pm2;\pm1\right\}\)

Từ đó bạn tìm những giá trị của x nha!