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1. Solve the equation: (x-4)^2-28=8

Show your work. Don’t forget that you will get two answers. Use the square root property to solve

2. This is Josh’s solution for the equation :
Step 1: x² - 6x – 7 = 0
Step 2: x² - 6x = 7
Step 3: x² - 6x + 9 = 7 + 9
Step 4: (x – 3)² = 16
Step 5: x – 3 = 16
Step 6: x = 19
Step 7: x – 3 = -16
Step 8: x = -13

Where did Josh make his mistake? What are the solutions to this equation? Show all of your work. This problem is solved using completing the square.

The mistake was in step _____________. Here is how to correctly solve the equation:

2 Answers

7 votes
Josh made his mistae in Step 5! Hope this helps with one!
User Pacukluka
by
8.3k points
3 votes
1. (x-4)^2-28 = 8
(x-4)^2 = 36, we square both sides and get;
x-4 = 6, x = 10
and
x-4 = -6, x = -2
2. The mistake was in step 5.
x² - 6x – 7 = 0; x² - 6x = 7; x² - 6x + 9 = 7 + 9; (x – 3)² = 16
x – 3 = 4; x = 7
x – 3 = -4; x = -1
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Hope this helps!
User Mark Costello
by
8.1k points