Answer
B) 8 or D) 17
Step-by-step explanation
Let's call x to one unknown number and y to the other number.
If one number is 9 more than another number, then:
[tex]y=x+9\text{ \lparen eq. 1\rparen}[/tex]
Given that the sum of the numbers is 25, then:
[tex]x+y=25\text{ \lparen eq. 2\rparen}[/tex]
Substituting equation 1 into equation 2 and solving for x:
[tex]\begin{gathered} x+x+9=25 \\ 2x+9=25 \\ 2x+9-9=25-9 \\ 2x=16 \\ \frac{2x}{2}=\frac{16}{2} \\ x=8 \end{gathered}[/tex]
Substituting x = 8 into the first equation:
[tex]\begin{gathered} y=8+9 \\ y=17 \end{gathered}[/tex]
Then, one of the numbers is 8 and the other one is 17
