10 + 10 + 10 + 20 + 20 + 20 + 30 + 30 + 30

=10 x 3 + 20 x 3 + 30 x 3

=(10 + 20 + 30) x 3

=60 x 3

=180

=

a x ( b + c)=> a x b + a x c

a x ( b - c ) => a x b - a x c

20 + 20 + 20 + 20 + 20 + 30 + 30 + 30 + 30 + 30

=20 x 5 + 30 x 5

=100 + 150

=250

=> a : b : c = 80 : 10 : 30 = 80 : 30 = \(\dfrac{4}{15}\)

We have:

30 : (2 + 1) = 10 (quarters)

The answer is : 10 + 5 = 15 (quarters)

g(-  4) + f(10) = (-4)²  2 . (-4) + 5 + 3 . 10 - 4

=16 + 8 + 5 + 30 - 4

=55

x . 3 + x . 2 = 50                                   x . 5 + x . 3 = 120 

x . (3 + 2) = 50                                     x . (5 + 3) = 120

x . 5 = 50                                              x . 8 = 120

x = 50 : 5                                              x = 120 : 8

x = 10                                                   x = 15

The question is wrong

This numbers is:

3²(2 . 5) = 9 . 10 = 90

Answer : 90

The edge of the cube is:\(\sqrt[3]{8}\) = 2 (units)

The answer is:\(\dfrac{2}{2}\) = 1 (unit)

The produc: 2, 4999 . 3,9999 . 4,9999 = 49,99575011

Answer: 50

We have:

\(\dfrac{21}{3}\) > 1                                     \(\dfrac{5}{9}\) < 1

=> \(\dfrac{21}{3}\) > \(\dfrac{5}{9}\)

We have:

\(\dfrac{22}{67}\) < \(\dfrac{22}{66}\) = \(\dfrac{1}{3}\)                                             

\(\dfrac{51}{152}\) > \(\dfrac{51}{153}\) = \(\dfrac{1}{3}\)

=> \(\dfrac{22}{67}\) < \(\dfrac{51}{152}\)

We have:

\(\dfrac{-45}{47}\) > -1                          \(\dfrac{31}{-30}\) < -1

=> \(\dfrac{-45}{47}\) > \(\dfrac{31}{-30}\)

The answer is: 3 x 4 x 2 = 24(days)

a(b - c) + b(c - a) + c(a - b)

=ab - ac + bc - ab + ca - cb

=0

a(bz - cy) + b(cx - az) + c(ay - bx)

=abz - acy + bcx - abz + acy - bcx

=0

 123 + 123 + 123 + 123               234 + 234 + 234 + 234

=123 x 4                                   = 234 x 4

=492                                         =  936

You should post the question in English

The answer is: 6 numbers