Problema Solution
the lenght of the side of a rectangular desk is given by 9x-2y cm. The lenght of the front is given by 9x+2y cm. what is an algebraic expression for the area of the top of the rectangular desk include correct units as part of the answer
Answer provided by our tutors
The area is the length times the width, or (9x-2y)(9x+2y).
Use FOIL to multiply them together (first,outer,inner,last). Then combine like terms.
81x^2 + 18y - 18y -4y^2 = 81x^2 - 4y^2 is the expression for the area.
*Also, notice this is a "difference of two squares" multiplication. When you multiply two binomials that are the same except for the -/+ sign the result is just the entire first term squared minus the entire second term squared.