twice a number added with thrice another number is 21. find the numbers if the difference between them is 3.

Answer 1

2x + 3y = 21

x-y =3

2x-2y = 6

subtract 3rd equation from the 1st to eliminate one variable

leaving

5y = 15

y = 15/5 = 3

x =6

the numbers are 3 and 6

or

2x+3y = 21

y-x = 3

2y-2x = 6

add last equation from to the 1st to get

5y = 27

y = 27/5 = 5.4

x = 2.4

the numbers are 2.4 and 5.4

or 3 and 6

2(2.4) +3(5.4) = 4.8+16.2 = 21

2(6) +3(3) = 12+9 = 21