How many of the numbers between 20 and 40 are prime numbers?
2 answers:
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Answer:
x = ± - 2
Step-by-step explanation:
x² + 4x = 4
to complete the square
add ( half the coefficient of the x- term )² to both sides
x² + 2(2)x + 4 = 4 + 4
(x + 2)² = 8 ( take square root of both sides )
x + 2 = ± ( subtract 2 from both sides )
x = ± - 2