Solve for all possible values of x.

square root of the quantity x minus 9 end quantity plus 4 equals 8

a) x = −5
b) x = 7
c) x = 13
d)x = 25

Respuesta :

Answer:

Option d)  x = 25

Step-by-step explanation:

we have

[tex]\sqrt{x-9}+4=8[/tex]

Solve for x

Subtract 4 both sides

[tex]\sqrt{x-9}+4-4=8-4[/tex]

[tex]\sqrt{x-9}=4[/tex]

squared both sides

[tex](x-9)=(+/-)4^2[/tex]

[tex](x-9)=(+/-)16[/tex]

Adds 9 both sides

[tex]x=9(+/-)16[/tex]

[tex]x1=9(+)16=25[/tex]

[tex]x2=9(-)16=-7[/tex]

Verify

1) For x=25

[tex]\sqrt{25-9}=4[/tex]

[tex]\sqrt{16}=4[/tex]

[tex]4=4[/tex] ----> is true

therefore

x=25 is a solution

2) For x=-7

[tex]\sqrt{-7-9}=4[/tex]

[tex]\sqrt{-16}=4[/tex]

The radicand cannot be a negative number

therefore

x=-7 is not a solution