Keywords
linear equation, variables
Step 1
Define the variables
Let
x-----> number of erasers
y-----> total cost
we know that
[tex]y=3(0.28)+(0.38)x[/tex]
[tex]y=0.84+(0.38)x[/tex] ------> this is the linear equation that represent the situation
therefore
the answer is
[tex]y=0.84+(0.38)x[/tex]