Answer:
[tex](13)\ 1 <x < 15[/tex]
[tex](14)\ 6 <x < 18[/tex]
Step-by-step explanation:
Question 13:
[tex]a,b = 8,7[/tex] -- the two sides
Using triangle inequality theorem, we have:
[tex]a + b > x[/tex]
[tex]a + x > b[/tex]
[tex]x + b > a[/tex]
So, we have:
[tex]a + b > x[/tex]
[tex]8 + 7 > x[/tex]
This gives:
[tex]15 > x[/tex]
[tex]a + x > b[/tex]
[tex]8 + x > 7[/tex]
Collect and evaluate like terms
[tex]x > -1[/tex]
[tex]x + b > a[/tex]
[tex]x + 7 > 8[/tex]
Collect and evaluate like terms
[tex]x > 1[/tex]
Ignore the inequality with a negative value.
So, we have:
[tex]x > 1[/tex] and [tex]15 > x[/tex]
Rewrite as:
[tex]1< x[/tex] and [tex]x < 15[/tex]
Merge
[tex]1 <x < 15[/tex]
Question 14:
[tex]a,b = 12,6[/tex] -- the two sides
Using triangle inequality theorem, we have:
[tex]a + b > x[/tex]
[tex]a + x > b[/tex]
[tex]x + b > a[/tex]
So, we have:
[tex]a + b > x[/tex]
[tex]12 + 6 > x[/tex]
This gives:
[tex]18 > x[/tex]
[tex]a + x > b[/tex]
[tex]12 + x > 6[/tex]
Collect and evaluate like terms
[tex]x > -6[/tex]
[tex]x + b > a[/tex]
[tex]x + 6 > 12[/tex]
Collect and evaluate like terms
[tex]x > 6[/tex]
Ignore the inequality with a negative value.
So, we have:
[tex]x > 6[/tex] and [tex]18 > x[/tex]
Rewrite as:
[tex]6< x[/tex] and [tex]x < 18[/tex]
Merge
[tex]6 <x < 18[/tex]