Answer:
x = 10.5
Step-by-step explanation:
given the equation
(x - 20)² = x² - 20 ← expand (x - 20)² using FOIL
x² - 40 x + 400 = x² - 20 ( subtract x² from both sides )
- 40x + 400 = - 20 ( subtract 400 from both sides )
- 40x = - 420 ( divide both sides by - 40 )
x = 10.5
