Answer:
[tex]Bill\to 9\ years[/tex]
[tex]H \to 16\ years[/tex]
Step-by-step explanation:
Let
[tex]H \to Hoang[/tex]
[tex]B \to Bill[/tex]
Currently:
[tex]H = B + 7[/tex]
Two years ago
[tex]H - 2 = 2 * (B -2)[/tex]
Required
H and B
We have:
[tex]H - 2 = 2 * (B -2)[/tex]
Open bracket
[tex]H -2 =2B - 4[/tex]
Add 2 to both sides
[tex]H -2+2 =2B - 4+2[/tex]
[tex]H =2B -2[/tex]
Substitute [tex]H = B + 7[/tex]
[tex]B + 7 =2B -2[/tex]
Collect like terms
[tex]2B - B =7+2[/tex]
[tex]B = 9[/tex]
Substitute [tex]B = 9[/tex] in [tex]H = B + 7[/tex]
[tex]H = B + 7[/tex]
[tex]H = 9 + 7[/tex]
[tex]H = 16[/tex]