Question

encontre o valor de 'x' e 'y'

a ) × +5 y = 30
3 - 5 y = 10

Answer 1

3-5y=10
3-10=5y
-7=5y
-7/5=y
-1,4=y
y=1,4 
agora substitui o valor de y 
x+5y=30
x+5*(1,4)=30
x+7=30
x=30-7
x=23

Answer 2

 × +5 y = 30
3x - 5 y = 10
    4x = 40 ==> x = 10
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x + 5y = 30 ==> 5y = 30 - x ==> 5y = 30-10 ==> 5y = 20 ==> y = 4