<h3>
Answer:</h3>
sin(Y) = 4/5
<h3>
Step-by-step explanation:</h3>
The sine of one of a pair of complementary angles is equal to the cosine of the other. Given that ∠X and ∠Y are complementary, sin(Y) = cos(X) = 4/5.
_____
You can figure this from SOH CAH TOA, the mnemonic that reminds you of the definitions of the trig functions. The adjacent leg for one of the acute angles in the right triangle is the opposite leg for the other angle.
... Sin = Opposite/Hypotenuse
... Cos = Adjacent/Hypotenuse
Step 1: Factor

1. <span> Multiply 2 by -2, which is -4.</span>
2. <span>Ask: Which two numbers add up to -3 and multiply to -4?
</span>3. <span>Answer: 1 and -4
</span>4. Rewrite

as the sum of

and


Step 2: <span>Factor out common terms in the first two terms, then in the last two terms.
</span>

<span>
Step 3: </span>Factor out the common term


Step 4: Solve for

1. Ask: When will

equal zero?
2. Answer: When

or

3. <span>Solve each of the 2 equations above:
</span>

<span>
Step 5: </span>From the values of

<span>above, we have these 3 intervals to test.
x = < -1/2
-1/2 < x < 2
x > 2
Step 6: P</span><span>ick a test point for each interval
</span>For the interval

Lets pick

Then,

After simplifying, we get

, Which is false.
Drop this interval.
<span>
For this interval

Lets pick

. Then,

. After simplifying, we get

which is true. Keep this <span>interval.
For the interval </span>

Lets pick

Then,

After simplifying, we get

, Which is false. Drop this interval.
.Step 7: Therefore,

Done! :)</span>
Answer:
b slow
Step-by-step explanation:
Answer:
$24.15
Step-by-step explanation:
What you do is you take 15% and make it into a decimal which is .15.
Then you times it by $21. 21*.15=3.15.
You then take the $3.15 and add it to $21 to get
$24.15 as your answer.