To solve the quadratic equation 3 ( x − 4 ) 2 = 75 , we need to find the values of x . Let's solve it step-by-step:
Divide Both Sides by 3 :
Start by simplifying the equation by dividing both sides by 3:
( x − 4 ) 2 = 3 75
( x − 4 ) 2 = 25
Take the Square Root of Both Sides :
Taking the square root on both sides will give us:
x − 4 = ± 5
This tells us that x − 4 can be either 5 or -5.
Solve for x :
If x − 4 = 5 , then:
\[x = 5 + 4 = 9\]
If x − 4 = − 5 , then:
\[x = -5 + 4 = -1\]
Thus, the solutions to the equation are x = 9 and x = − 1 .
Therefore, the correct answer is option D: x = − 1 and x = 9 .