Question

Sabendo que o valor de a=7 encontre o valor de b
a) a/2-b=-2


b) 8/a+2b=10

Answer 1

a)

a/2 - b = - 2 <=>

<=> 7/2 - b = - 2 <=>

<=> 7/2 + 2 = b <=>

<=> 7/2 + 4/2 = b <=>

<=> (7+4)/2 = b <=>

<=> 11/2 = b

Logo, b = 11/2.

b)

8/a + 2b = 10 <=>

<=> 8/7 + 2b = 10 <=>

<=> 2b = 10 - 8/7 <=>

<=> 2b = 70/7 - 8/7 <=>

<=> 2b = (70-8)/7 <=>

<=> 2b = 62/7 <=>

<=> b = (62/7)/2 <=>

<=> b = 62/(7x2) <=>

<=> b = 62/14 <=>

<=> b = 31/7

Logo, b = 31/7.