Resolva os problemas: a) x^2 - 10x + 25 = 0
b) x^2 - 4x - 5 = 0

(preciso da montagem da conta, junto com o resultado)

Step-by-step 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

hello,

b) 62.47% of the students are between 14 and 18 years old.

step-by-step explanation:

mean = 15 and standard deviation = 2

student between 14 to 18

formula used z-score

for age 14 , z score

using z-table , p(z> -0.5)=0.3085

for age 18 , z score

using z-table , p(z< 1.5)=0.9332

p(-0.5< z< 1.5)=0.9332-0.3085 = 0.6247

thus, 62.47% of the students are between 14 and 18 years old.

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step-by-step explanation:

the correct answer would be:

220 centimeters

to get this you can use the pythagorean theorem

hope this

step-by-step explanation: