Subtract the second equation from the first
1 answer:
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Answer:
Option A. The cost of one pack of ballpoint pens is $3 and the cost of one pack of gel pens is $7.
Step-by-step explanation:
Let
x -----> the cost of one pack of ballpoint pens
y -----> the cost of one pack of gel pens
we know that
60x+25y=355 -----> equation A
120x+30y=570 -----> equation B
Solve the system of equations by graphing
Remember that the solution of the system is the intersection point both graphs
The solution is the point (3,7)
see the attached figure
therefore
The cost of one pack of ballpoint pens is $3
The cost of one pack of gel pens is $7
