Q: Solve: 3 + 2(x – 5)² = 21
A: OK, we start:
3 + 2(x – 5)² = 21
[subtract 3 from both sides]
2(x – 5)² = 18
Now, divide both sides by 2:
(x – 5)² = 9
Square-root both sides… Remember to include the +/- whenever you square-root:
√(x – 5)² = ±√9
(x – 5) = ±3
x – 5 = ±3
Add 5 to both sides:
x = ±3 + 5
So, x = 3 + 5 OR x = -3 + 5
x = 8 OR x = 2
