Question

Plz answer question no. 14,16,21​

Answer 1

Answer:

14.(a-b)^3=a^3-b^3-3ab(a-b)

Step-by-step explanation:

(2a -3b)^3=a^3-b^3-3ab(a-b)

27=a^3-b^3-3(2)(a-b)

21.(a+b)^3...and solve using this formula

Answer 2

Answer:34

Step-by-step explanation:

let the two digit no be xy

required no = 10x+y

reversed no =10y+x

According to the question

(10x+y)- 4(x+y) = 6.........1st equation

(10y+x)-(10x+y)=9..........2nd equation

10x+y-4x-4y=6

10y+x-10x-y=9

6x-3y=6...........now this is our 1st eq

-9x+9y=9................................... 2nd eq

multiplying 1st eq by 3 we get

18x-9y=18

-9x+9y=9

applying alimenation method

9x=27

x = 3

putting the value in 2nd eq, we get

6x-3y=6

6*3-3y=6

18-3y=6

-3y=6-18

-3y=-12

y= -12/-3

y=4

So, the no was considered xy

i.e. 34 .......