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3 years ago

Help on these precalc problems 14-20

Mathematics

1 answer:

Nadya [2.5K]3 years ago

7 0

15) factor out cos: cos(x)(sin(x)+1)=0
Now this is true when either cos(x)=0 (x=pi/2 and 3pi/2)
Or when sin(x)=-1 (x=3pi/2)
So it's solutions are pi/2 and 3pi/2

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7 - 5n = 6 + 6(n + 2)

postnew [5]

7- 5n=6+6(n+2)
7- 5n=6+6n+12
7 -5n=18+6n
5n-6n=18-7
-11n=11
n=-1

4 0

3 years ago

If (ax+2)(bx+7)=15x2+cx+14 for all values of x, and a+b=8, what are the 2 possible values fo c

dolphi86 [110]

Given:

$(ax+2)(bx+7)=15x^2+cx+14$

And

$a+b=8$

Required:

To find the two possible values of c.

Explanation:

Consider

$\begin{gathered} (ax+2)(bx+7)=15x^2+cx+14 \\ abx^2+7ax+2bx+14=15x^2+cx+14 \end{gathered}$

$\begin{gathered} ab=15-----(1) \\ 7a+2b=c \end{gathered}$

And also given

$a+b=8---(2)$

Now from (1) and (2), we get

$\begin{gathered} a+\frac{15}{a}=8 \\ \\ a^2+15=8a \\ \\ a^2-8a+15=0 \end{gathered}$ $a=3,5$

Now put a in (1) we get

$\begin{gathered} (3)b=15 \\ b=\frac{15}{3} \\ b=5 \\ OR \\ b=\frac{15}{5} \\ b=3 \end{gathered}$

We can interpret that either of a or b are equal to 3 or 5.

When a=3 and b=5, we have

$\begin{gathered} c=7(3)+2(5) \\ =21+10 \\ =31 \end{gathered}$

When a=5 and b=3, we have

$\begin{gathered} c=7(5)+2(3) \\ =35+6 \\ =41 \end{gathered}$

Final Answer:

The option D is correct.

31 and 41

8 0

1 year ago

Giving brainliest !! *easy*

Zepler [3.9K]

Answer: 49

Step-by-step explanation:

The missing constant term in the perfect square is 49.

x^2 + 14x + 49

We need a squart root of something to make the factor add up equal to 14x. If it's a perfect square, we could divide 14 by 2, 14/2 = 7, and we multiply 7^2, we get 49, which is a perfect square.

4 0

2 years ago

Directions: Determine how much Marco would be paid

lidiya [134]

Answer:

766.87 is how much he is paid in all.

Step-by-step explanation:

2.5% of 75 is 1.875. 1.875 times 9 is 16.875. 75 times ten is 750. add together to get the whole.

7 0

2 years ago

Mike wants to make meatloaf . His recipe uses a total of 5 pounds of meat . If he use a 3 to 1 radio of beef to pork how much po

Sergio [31]

Answer:

1 and 2/3

Step-by-step explanation:

5/3 = 1 and 2/3 * 1 = 1 and 2/3

4 0

3 years ago