Question

factorise : X²+12 x+21
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Answer 1

Answer:

-12+2√15/2 or -12-2√15/2

Step-by-step explanation:

b²-4ac= 12²-4x1x21

= 60

x=-b±√b²-4ac/2a

-12±√60/2

x= -12+2√15/2 or x = -12-2√15/2