K×x+8=4
k×x=4-8
k×x=-4
x=-4/k
X^2 - xy + xy - Y^2
=
X^2 - Y^2
The formula of a volume of a cuboid:

l - length
w - width
h - height
We have:
l = (x + 4) cm
w = (x + 1) cm
h = 3 cm
Substitute:
<em>use distributive property</em>


<em>combine like terms</em>
