Answer:
The two digit numbers are 13 and 17.
Step-by-step explanation:
Firstly, you have to form a simultaneous equation. The information is when 2 number are added equals to 30 and when substracted is equals to 4 or -4. Let variable to represents the number :
Let x be 1st number,
Let y be 2nd number,
[tex]x + y = 30 - - - - (1)[/tex]
[tex]x - y = 4 - - - - (2)[/tex]
Then you have to solve these simultaneous equation :
[tex](1) - (2)[/tex]
[tex]x - x + y - ( - y) = 30 - 4[/tex]
[tex]y + y = 26[/tex]
[tex]2y = 26[/tex]
[tex]y = 13[/tex]
Substitute y = 13 into (2),
[tex]x - 13 = 4[/tex]
[tex]x - 13 + 13 = 4 + 13[/tex]
[tex]x = 17[/tex]
