3/10 times 2/3 3 times 2 is 5 and 10 times 3 is 30 5/30 a
We need to call for x minute
+ Phone Company A charges a monthly fee of $42.50, and $0.02 for each minute talk time. So we have to spend: <span>$42.50+ $0.02x
+ </span>Phone company B charges a monthly fee of $25.00, and $0.09 for each minute of talk time. So we have to spend: <span>$25.00+ $0.09x
We solve for x: </span>$42.50+ $0.02x> <span>$25.00+ $0.09x
or </span>$42.50- $25.00 > $0.09x- <span>$0.02x
and we have $0.07x<$27.50
or x< 27.50:0.07 and x< 393.86
The answer is:
If we have to call much time, at least 394 minutes, we should choose A
If not, choose B</span>
Answer:
10 in
Step-by-step explanation:
There are two ways to work this problem, and they give different answers. The reason for that is that <em>the data shown in the diagram is not consistent</em>.
<u>Method 1</u>
Use the area to determine the base length. The area formula is ...
A = (1/2)bh
20 in^2 = (1/2)(b)(4 in)
(20 in^2)/(2 in) = b = 10 in
The missing side dimension is 10 inches.
__
<u>Method 2</u>
Use the Pythagorean theorem to find the parts of the base, then add them up.
Left of the "?" we have ...
left^2 +4^ = 6^
left^2 = 36 -16 = 20
left = √20 = 2√5
Right of the "?" we have ...
right^2 +4^2 = 8^2
right^2 = 64 -16 = 48
right = √48 = 4√3
So, the base length is ...
base = left + right = 2√5 +4√3
base ≈ 11.400 in
The missing side dimension is 11.4 inches. (The area is 22.8 in^2.)
Answer:
Step-by-step explanation:
Using the addition formulae for cosine
cos(x ± y) = cosxcosy ∓ sinxsiny
---------------------------------------------------------------
cos(120 + x) = cos120cosx - sin120sinx
= - cos60cosx - sin60sinx
= - 
cosx - 
sinx
squaring to obtain cos² (120 + x)
= 
cos²x + sinxcosx + 
sin²x
--------------------------------------------------------------------
cos(120 - x) = cos120cosx + sin120sinx
= -cos60cosx + sin60sinx
= - cosx + sinx
squaring to obtain cos²(120 - x)
= cos²x - sinxcosx + sin²x
--------------------------------------------------------------------------
Putting it all together
cos²x + cos²x + sinxcosx + sin²x + cos²x - sinxcosx + sin²x
= cos²x + cos²x + sin²x
= cos²x + sin²x
= (cos²x + sin²x) =
