I cannot evaluate this expression using the order of operations I know of, can someone explain it for me?

[Bones]

$$b-y(y^4-b)-7$$$$(y=2,b=7)$$
My work:
$$7-2(2^4-7)-7$$$$7-2(16-7)-7$$$$7-2(9)-7$$$$7-18-7$$$$-11-7$$$$-18$$
Worksheet's Answer:
$$38$$

 

[Otis]

Worksheet's Answer: 38

Hi Bones. You did good. The worksheet's answer is not correct.
$\;$

 

[blamocur]

You'd get 38 for $(b-y)(y^4-b)-7$.

 

[Dr.Peterson]

You'd get 38 for $(b-y)(y^4-b)-7$.

... which is a mistake beginners often make! Good for you.

 

[Bones]

Oh okay. Thanks guys