The answer is either
or 
To solve: Let's solve your equation step-by-step.
5x2+5x−x2−x=2004
Step 1: Simplify both sides of the equation.
4x2+4x=2004
Step 2: Subtract 2004 from both sides.
4x2+4x−2004=2004−2004
4x2+4x−2004=0
Step 3: Use quadratic formula with a=4, b=4, c=-2004.
x=
−b±√b2−4ac
/2a
x=
−4±√32080
/8
or 
you can buy 5 books and have a $1 left over I think Hope this a helps! :D
Each side should increase by 2x (left & right, and up & down) so that to match the condition :
7+2x)(6+2x) = 45
Solving it will give you: 4x² + 26x - 3
Answer:
C
Step-by-step explanation:
longer leg/shorter leg = longer leg/shorter leg
10/5 = 5/2.5