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  • Usuário do Brainly
2014-08-21T01:06:30-03:00
X² -Sx + P=0

S=2+7=9
P=2×7=14

x²-9x +14=0

vamos conferir
a=1
b=-9
c=14
Δ=b²-4ac
Δ=81-56
Δ=25
√Δ=√25
√25= ± 5

x=(-b ± √Δ)/2a

x'= \frac{9+5}{2} = \frac{14}{2} =7

x"= \frac{9-5}{2} = \frac{4}{2} =2

Logo confere
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