So because we are working backwards then we want to isolate the variable so we multiply 9 to each side and the /9 x9 crosses out and 2 x9 = 18 so x= 18 I hope that helps
Suppose we let 
, so that 
.
Also, recall the double angle identity for cosine:
So, we can rewrite and compute the integral using the substitution, as
Answer:
n = -7,6
Step-by-step explanation:
n(n+1)+3=45
distributive property: a(b+c) = ab+ac
n²+n+3 = 45
n²+n -42 = 0
factor now
(n+7)(n-6) = 0
n = -7,6
You can express the edge lengths in terms of "cubes" or you divide the total volume by the volume of a cube. It works either way.
Edge lengths are
.. 80 cubes by 8 cutes by 13 cubes
so total volume is
.. (80 * 8 * 13) = 8320 cubes
In cubic inches, the volume is
.. (20 in)*(2 in)*(3 1/4 in) = 130 in^3.
The volume of a 1/4-in cube is (1/4 in)^3 = 1/64 in^3.
Then the number of cubes that will fit in the prism is
.. (130 in^3)/(1/64 in^3) = 8320 . . . . cubes
8320 cubes are needed to fill the rectangular prism.
