The product (x + 3y)(3x – y) =

3x²-3y²+8xy

Step-by-step explanation:

When you multiply two factors, you want to use the FOIL method.

First

Outer

Inner

Last

(x+3y)(3x-y)                  [distribute by FOIL]

3x²-xy+9xy-3y²            [combine like terms]

3x²+8xy-3y²                 [rewrite]

3x²-3y²+8xy

Now, we know the product is 3x²-3y²+8xy.

congruent segments

step-by-step explanation:

geometry: triangles

solvers

lessons

answers archive

call the larger triangle abc

then the smaller triangle cde is similar to abc (all angles are equal, aaa).  

ab is the side that is 36, and we wish to find de, the side corresponding to ab

area_cde = area_abc - area_cde --> area_abc / area_cde = 2

let x=length of de

ratio of areas = (ratio of sides)^2

+2+=+%2836%2fx%29%5e2+

+2+=+1296%2fx%5e2+

++x%5e2+=+1296%2f2+=+648+

25.45584