Answer:
Explanation:
a) x² - 10x + 25 = 0
(x-5)²=0
x-5=0
x=5
b) x² - 4x - 5 = 0
⇒ ( x 2 − 4 x + 4 ) − 5 − 4 = 0
⇒ ( x 2 − 4 x + 4 ) − 9 = 0
( x − 2 ) 2 − 9 = 0 ⇒
( x − 2 ) 2 = 9 ⇒
( x − 2 ) = ± √ 9 (don't forget the ± !) ⇒
x= − 1 x = 5
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