Answer:
x = 2 ± 2√5 Exact solution
x = {-2.472, 6.472} Decimal approximation
Step-by-step explanation:
x² - 4x + 4 = 20
Subtract 4 from both sides
x² - 4x = 16
Complete the square using half the x coefficient, (-4/2 = -2), as the complete the square term
(x - 2)² = (-2)² + 16
(x - 2)² = 20
Take the square root of both sides
x - 2 = ±√20
x - 2 = ±2√5
Add 2 to both sides
x = 2 ± 2√5 Exact solution
x = {-2.472, 6.472} Decimal approximation
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Note this could also be solved using the quadratic formula
