[tex]\text{We're trying to find the cost of the pillow after the markdown}\\\\\text{We know that the original cost of a pillow is \$15}\\\\\text{We also know that the customer was marked 5\% down from the}\\\text{original cost}\\\\\text{To find the cost, multiply 15 by 0.05 and subtract}\\\\15*0.05=0.75\\\\15-0.75 = 14.25\\\\\boxed{\$14.25}[/tex]