Respuesta :

rebeccarayshma

Answer:

y = 20

Step-by-step explanation:

[tex]9 - \sqrt{y - 4} = 5[/tex]

i) move 9 to the right-hand side and change its sign

[tex] - \sqrt{y - 4} = 5 - 9[/tex]

ii) calculate the difference

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

iii) change the signs on both sides of the equation

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

iv) square both sides of the equation

[tex]( \sqrt{y - 4} ) {}^{2} = 4 {}^{2} [/tex]

[tex]y - 4 = 4 {}^{2} [/tex]

[tex]y - 4 = 16[/tex]

v) move -4 to the right-hand side and change its sign

[tex]y = 16 + 4[/tex]

vi) add the numbers

[tex]y = 20[/tex]

Answer: y = 20

defined condition is y ≥ 4

[tex]9 - \sqrt{y - 4}=5\\\\<=> \sqrt{y - 4}= 9-5\\\\\\<=>\sqrt{y-4}= 4\\\\\\=> y - 4 = 16\\\\\\<=> y = 16 + 4 = 20[/tex]

Step-by-step explanation: