In which step did Cyrus make an error?

7 7 (x - 1)² = 12

(x - 1)2 = 36 Step 1

I-1= 6

Step 2

I=7

Step 3

In step 2 Cyrus make an error.

Step-by-step explanation:

Given : Expression

To find : In which step did Cyrus make an error?

Solution :

Expression

Step 1 -

Step 2 -

Step 3 -

There is a mistake in step 2,

As we are taking root both side so RHS value is +6 and -6.

So that there are two solutions of the equation.

Correct steps are,

Step 2 -

Step 3 -

Therefore, In step 2 Cyrus make an error.