Answer:
Markup of _66.67_ % or $ _33,92_ per pair of boots
Step-by-step explanation:
In order to find the markup per pair of boots, we need to find the sales price BEFORE tax.
That can be done simply with a cross-multiplication (106.25 represents total price with 6.25% tax, and 100 represent amount of sales before tax)

if we isolate x we have x = (90.10 * 100) / 106.25 = $84.80
We can then easily calculate the markup amount, since the boots were sold $84.80 and Marissa paid $50.88, that means her markup amount is $33.92.
Now, let's calculate the markup percentage by see how much $33.92 represents compared to the initial price of $50.88:
$33.92 / $50.88 = 66.67%
Hello,
Answer B
x^4-52x²+576=0
==>x^4-16x²-36x²+576=0
==>x²(x²-16)-36(x²-16)=0
==>(x²-16)(x²-36)=0
==>(x+4)(x-4)(x+6)(x-6)=0