Suppose the two numbers are x and y. According to the question;

x+Y=29 EQ1

x-y=17 EQ2

x=y+17 EQ3

put in the first equation

y+17+y=29

2y+17=29

2y=29-17

2y=12

y=12/2

y=6

Put the value of y in EQ3

x=y+17

x=6+17

x=23

so two numbers are 23 and 6

x+Y=29 EQ1

x-y=17 EQ2

x=y+17 EQ3

put in the first equation

y+17+y=29

2y+17=29

2y=29-17

2y=12

y=12/2

y=6

Put the value of y in EQ3

x=y+17

x=6+17

x=23

so two numbers are 23 and 6