Se x+y=10 e x-y=7 , dê o valor numérico de:
a) 2x+3y
b)-2x+y
c)x/2+y/3
Soluções para a tarefa
Respondido por
9
Se
e 


Adicionando, temos






Assim:
a)
b)
c)
Adicionando, temos
Assim:
a)
b)
c)
Respondido por
9
x+y=10==. y = 10 - 17/2 ==> y= (20-17)/2 ==> y = 3/2
x-y=7
2x = 17
x = 17/2
a) 2x+3y ==> 2. 17 + 3.3 ==>34 +9 ==> 43
2 2 2 2
b)-2x+y = - 2 . 17 + 3 ==> - 34 + 3 ==> - 31
2 2 2 2
c)x/2+y/3 = 17/2 + 3/2 ==> 17 + 3 ==> 51 + 6 ==> 57
2 3 4 6 12 12
x-y=7
2x = 17
x = 17/2
a) 2x+3y ==> 2. 17 + 3.3 ==>34 +9 ==> 43
2 2 2 2
b)-2x+y = - 2 . 17 + 3 ==> - 34 + 3 ==> - 31
2 2 2 2
c)x/2+y/3 = 17/2 + 3/2 ==> 17 + 3 ==> 51 + 6 ==> 57
2 3 4 6 12 12
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