9x + 2² . 5 = 10²

9x + 4 . 5 = 100

9x + 20 = 100

9x = 100 - 20

9x = 80

x = 80 : 9

x = 80/9

Chúc bạn học tốt!! ^^

Ta có: \(9x+2^2\cdot5=10^2\)

nên 9x=80

hay \(x=\dfrac{80}{9}\)

9x + 2² . 5 = 10²

9x + 4 . 5 = 100

9x + 20 = 100

9x = 100 - 20

9x = 80

x = 80 : 9

x = 80/9

Chúc bạn học tốt!! ^^

Ta có: \(9x+2^2\cdot5=10^2\)

\(\Leftrightarrow9x=100-20=80\)

hay \(x=\dfrac{80}{9}\)

9x + 2² . 5 = 10²

9x + 4 . 5 = 100

9x + 20 = 100

9x = 100 - 20

9x = 80

x = 80 : 9

x = 80/9

Ta có: \(9x+2\cdot3^2=3^4\)

\(\Leftrightarrow9x=81-18=63\)

hay x=7

\(9x+2.9=81\\ 9x+18=81\\ 9x=81-18\\ 9x=63\\ x=7\)

a)x=1

b)x=2

c)x=3

a, x= 1

b, x=2

c,x= 3

\(x^2=1\)

\(x^2=4=2^2\)

\(x^2=9=3^2\)

=> X x (12 - 9 - 2) = 72

=> X x 1 = 72 

=> X = 72

\(12\times x-9\times x-2\times x=72\\ =>x\times\left(12-9-2\right)=72\\ =>x\times1=72\\ =>x=72:1=72\)

1.goi ...a+b va a*b

a+b=a*b

ad+bc=ac

bc=ac-ad

bc=a(c-d)

........

a=c,b=c-d

2.2*a+b+2+a*b=9

a.(2-b)+(b+2).1=9

a)4/9 : x/6 = 2/3

           x/6 = 4/9 : 2/3

          x/6  =   2/3 = 4/6

vậy x = 4

b)x/5 x 3/7 = 9/35

   x/5          = 9/35 : 3/7

   x/5          = 3/5

vậy x = 3