Question

If ( 3 y − 9 ) 2 + 7 = 43 , then what is(are) the values of y?

Answer 1

Answer:

y = 5 and y = 1

Step-by-step explanation:

$\textsc {Subtract 7 from each side :}$

⇒ (3y - 2)² + 7 - 7 = 43 - 7

⇒ (3y - 2)² = 36

$\textsc {take the square root on each side :}$

⇒ √(3y - 9)² = √36

⇒ 3y - 9 = ±6

$\textsc {When equal to +6, add 9 on each side :}$

⇒ 3y - 9 + 9 = 6 + 9

⇒ 3y = 15

$\textsc {Divide by 3 on each side :}$

⇒ 3y/3 = 15/3

⇒ y = 5

$\textsc {When equal to -6, add 9 on each side :}$

⇒ 3y - 9 + 9 = -6 + 9

⇒ 3y = 3

$\textsc {Divide by 3 on each side :}$

⇒ 3y/3 = 3/3

⇒ y = 1