HELP ME FAST I WILL GIVE POINTS!!

Which shows the correct solution of the equation 1/2a+2/3b=50, when b=30?

X+ y = 5 ; x - y =3 solve using linear combination

Kayla made observations about the sellin price of a new brand of coffee that sold in the three different sized bags she recorded those observations in the following table 6 is $2.10 8 is $2.80 and 16 is to $5.60 use the relationship to predict the cost of a 20oz bag of coffee.