Answer:
15
Step-by-step explanation:
Given: y is directly proportional to [tex]\sqrt{x+2}[/tex] when x = 7, y = 9
To find: y when x = 23
Solution:
u and v are said to be proportional if [tex]u=kv[/tex] where k is a constant of proportionality.
As y is directly proportional to [tex]\sqrt{x+2}[/tex] when x = 7, y = 9,
[tex]y=k\sqrt{x+2}\\[/tex]
Put x = 7, y = 9
[tex]9=k\sqrt{7+2}=3k\\ k=\frac{9}{3}=3\\ y=3\sqrt{x+2}[/tex]
Put x = 23
[tex]y=3\sqrt{23+2}=3\sqrt{25}=3(5)=15[/tex]
