Question

se x+ y = 20 e x - y = 5 ,então log10 ( x2 - y2 ) e igual a :

a) 100 b) 2 c) 25 d)12,5

Answer 1

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Ola Maryla

x + y = 20
x - y = 5

x² - y² = (x + y)*(x - y) = 20*5 = 100

log(100) = 2 (B)

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