\(\Rightarrow4:\left(x+9\right)=60\\ \Rightarrow x+9=\dfrac{4}{60}=\dfrac{1}{15}\Rightarrow x=\dfrac{1}{15}-9=-\dfrac{134}{15}\)

4:(x + 9) - 5 = 55

<=> 4:(x + 9) = 60

<=> x + 9 = 15

<=> x = 15 - 9

<=> x = 6

\(4:\left(x+9\right)-5=55\)

\(\Leftrightarrow4:\left(x+9\right)=55+5\)

\(\Leftrightarrow4:\left(x+9\right)=60\)

\(\Leftrightarrow x+9=4:60\)

\(\Leftrightarrow x+9=\dfrac{1}{15}\)

\(\Leftrightarrow x=\dfrac{1}{15}-9\)

\(\Leftrightarrow x=-\dfrac{134}{15}\)

Mình trả lời rồi bạn nhé!

\(\dfrac{7}{x}<\dfrac{x}{4}<\dfrac{10}{x}\)

\(\Leftrightarrow 7<\dfrac{x^2}{4}<10\)

\(\Leftrightarrow 28< x^2<40\)

Vì x là số nguyên dương \(\Leftrightarrow x^2=36\)

Vậy \(x=6\)

\(\dfrac{7}{2}\) < \(\dfrac{2}{4}\)< \(\dfrac{10}{2}\)

x=2

2^x .4=128

2^x=128:4

2^x=32

=>x=5

2^x . 4 = 128

2^x = 128 : 4

2^x = 32

2^x = 2^5

--> x = 5

2 mũ x = 128 : 4 = 32

2 mũ x = 2 mũ 5 (  đổi 32 ra ý )

=> x = 5 chúc hok tốt 

(x+3)(x-2)+3x=4(x+3/4)

x(x+3)-2(x+3)+3x=4x+3

x²+3x-2x-6+3x-4x=3

x²+(3x-2x+3x-4x)-6=3

x²-6=3

x²=9

x²=3²

=>x=|3|

x=3 hoặc x=-3

\(\left(x+3\right)\left(x-2\right)+3x=4\left(x+\frac{3}{4}\right)\)

\(\Rightarrow x^2-2x+3x-6+3x=4x+3\)

\(\Rightarrow x^2+4x-6=4x+3\)

\(\Rightarrow x^2-6=3\)

\(\Rightarrow x^2=3+6=9\)

\(\Rightarrow x=-3\)hoặc \(x=3\)

(x+3)(x-2)+3x=4(x+3/4)

x(x+3)-2(x+3)+3x=4x+3

b)

46(x - 25) = 92

x - 25 = 92 : 46

x - 25 = 2

x = 2 + 25

x = 27

c)

4²x + 3²x = 75

16x + 9x = 75

25x = 75

x = 75 : 25

x = 3

p/s: mk chỉ giải nửa phần thôi =vv