This is publisher solution. You should check your work before submission. However, NEVER COPY THE SOLUTION DIRECTLY AS YOUR ASSIGNMENT WORK!
NEVER COPY THE SOLUTION! When you have problems, discuss with your classmates, as well as your teacher, read the solution only as your last resort.
NEVER COPY THE SOLUTION! Always try to write in your own words, calculate using your own method, and present in your own style!
NEVER COPY THE SOLUTION!