Let
x-------> the number of fiction books
y-------> the number of nonfiction books.
we know that
\(x+y=26\) -----> equation \(1\)
\(x=y+12\)
\(x-y=12\) -----> equation \(2\)
Add equation \(1\) and equation \(2\)
\(x+y=26\\x-y=12\\ ------\\ 2x=38\\ x=38/2\\x=19\ fiction\ books\)
find the value of y
\(x+y=26\)
\(19+y=26\)
\(y=26-19=7\ nonfiction\ books\)
therefore
the answer is
Part a) the number of fiction books is \(19\ fiction\ books\)
Part b) the number of nonfiction books is \(7\ nonfiction\ books\)
