It helps if you create equations for these problems.
1.) t= total p= amount of printers
The equation would be t=145p, since you have to multiply 145 by the amount of printers you are purchasing.
t=145(8)
The total for the printers would be $1,160. You can put 145*8 into a calculator.
Now do the same thing for the laptops.
2.) t= total l=laptop
t=439l
t=439(3)
t=$1,317
Three laptops cost more.