Question

A printing company sells small packages of personalized stationery for $7 each, medium

Answer 1

Step-by-step explanation:

what's the question ? it does not say.

I assume it is "how many packages of what size were sold ?"

x = number of small packages

y = number of medium packages sold

z = number of large packages sold

x + y + z = 9

7x + 12y + 15z = 86

y = 3z

these are the 3 equations we get out of the question.

we put the third equation into the other two :

x + 3z + z = x + 4z = 9

7x + 12×3z + 15z = 7x + 36z + 15z = 7x + 51z = 86

it of this first equation we get

x = -4z + 9

and putting that into the other equation :

7×(-4z + 9) + 51z = 86

-28z + 63 + 51z = 86

23z = 23

z = 1

y = 3z = 3×1 = 3

x = -4z + 9 = -4×1 + 9 = -4 + 9 = 5

so, 5 small, 3 medium and 1 large packages were sold.