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3 years ago

I NEED TO HAND IN NOW!!!

Mathematics

1 answer:

umka21 [38]3 years ago

5 0

Step-by-step explanation:

total no. of pupils is not more than 24

therefore first equation is

(x+y) ≤ 24. ....(1)

No. of girls exceeding the no. of boys by atleast 4

(y-x) ≥ 4. .....(2)

b) Now Liza chooses 8 boys

Maximum no. of girls = ?

Using first inequality

y+8= 24 ( maximum value of less than or equal to function is equal to itself)

Therefore,

y= 24-8

=16

Minimum no. of girls = ?

Using second inequality

y-8 =4 (minimum value of greater than or equal to function is equal to itself)

Therefore,

y= 4+8

y=12

Answer:

a) 2linear inequalities

(x+y) ≤ 24

(y-x) ≥ 4

b) Max no. of girls = 16

Min no. of girls = 12

Hope it helps...

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Let f(x)=5x3−60x+5 input the interval(s) on which f is increasing. (-inf,-2)u(2,inf) input the interval(s) on which f is decreas

o-na [289]

Answers:

(a) f is increasing at $(-\infty,-2) \cup (2,\infty)$ .

(b) f is decreasing at $(-2,2)$ .

(c) f is concave up at $(2, \infty)$

(d) f is concave down at $(-\infty, 2)$

Explanations:

(a) f is increasing when the derivative is positive. So, we find values of x such that the derivative is positive. Note that

$f'(x) = 15x^2 - 60
$

So,

$
f'(x) \ \textgreater \ 0
\\
\\ \Leftrightarrow 15x^2 - 60 \ \textgreater \ 0
\\
\\ \Leftrightarrow 15(x - 2)(x + 2) \ \textgreater \ 0
\\
\\ \Leftrightarrow \boxed{(x - 2)(x + 2) \ \textgreater \ 0} \text{ (1)}$

The zeroes of (x - 2)(x + 2) are 2 and -2. So we can obtain sign of (x - 2)(x + 2) by considering the following possible values of x:

-->> x < -2
-->> -2 < x < 2
--->> x > 2

If x < -2, then (x - 2) and (x + 2) are both negative. Thus, (x - 2)(x + 2) > 0.

If -2 < x < 2, then x + 2 is positive but x - 2 is negative. So, (x - 2)(x + 2) < 0.
If x > 2, then (x - 2) and (x + 2) are both positive. Thus, (x - 2)(x + 2) > 0.

So, (x - 2)(x + 2) is positive when x < -2 or x > 2. Since

$f'(x) \ \textgreater \ 0 \Leftrightarrow (x - 2)(x + 2) \ \textgreater \ 0$

Thus, f'(x) > 0 only when x < -2 or x > 2. Hence f is increasing at $(-\infty,-2) \cup (2,\infty)$ .

(b) f is decreasing only when the derivative of f is negative. Since

$f'(x) = 15x^2 - 60$

Using the similar computation in (a),

$f'(x) \ \textless \ \ 0 \\ \\ \Leftrightarrow 15x^2 - 60 \ \textless \ 0 \\ \\ \Leftrightarrow 15(x - 2)(x + 2) \ \ \textless \ 0 \\ \\ \Leftrightarrow \boxed{(x - 2)(x + 2) \ \textless \ 0} \text{ (2)}$

Based on the computation in (a), (x - 2)(x + 2) < 0 only when -2 < x < 2.

Thus, f'(x) < 0 if and only if -2 < x < 2. Hence f is decreasing at (-2, 2)

(c) f is concave up if and only if the second derivative of f is positive. Note that

$f''(x) = 30x - 60$

Since,

$f''(x) \ \textgreater \ 0
\\
\\ \Leftrightarrow 30x - 60 \ \textgreater \ 0
\\
\\ \Leftrightarrow 30(x - 2) \ \textgreater \ 0
\\
\\ \Leftrightarrow x - 2 \ \textgreater \ 0
\\
\\ \Leftrightarrow \boxed{x \ \textgreater \ 2}$

Therefore, f is concave up at $(2, \infty)$ .

(d) Note that f is concave down if and only if the second derivative of f is negative. Since,

$f''(x) = 30x - 60$

Using the similar computation in (c),

$f''(x) \ \textless \ 0 
\\ \\ \Leftrightarrow 30x - 60 \ \textless \ 0 
\\ \\ \Leftrightarrow 30(x - 2) \ \textless \ 0 
\\ \\ \Leftrightarrow x - 2 \ \textless \ 0 
\\ \\ \Leftrightarrow \boxed{x \ \textless \ 2}$

Therefore, f is concave down at $(-\infty, 2)$ .

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3 years ago

You are going to mix a gallon bucket of window cleaner. The instructions direct you to mix 1 part cleaner to 3 parts water. How

Pie

One gallon equals to 4 quarts.

The instructions tell you to add 1 part of cleaner and 3 parts of water, in total 4 parts. It makes it easy as you can take that one part = one quart.

You will use 3 quarts of water and 1 quart of cleaner. The answer is D.

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Answer:

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3 years ago

Find the values for x and y

USPshnik [31]

Answer:

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Step-by-step explanation:

Since all three sides are equal, as indicated by the lines on the sides, all three angles are equal

Since a triangle is equal to 180 degrees

180/3 = 60

Each angle is 60 degrees

x+5 = 60

Subtract 5 from each side

x +5-5 = 60-5

x = 55

y-10= 60

y-10+10 = 60+10

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Select the correct answer from each drop-down menu. Mallory goes to the farmers market every weekend. She buys six apples for $0

Zielflug [23.3K]

Answer:

a) The equation for the situation = 14.50 = 4.5 + 1.25n

b) The number of oranges she bought = 8 oranges

Step-by-step explanation:

Where n represents the number of oranges.

The equation is written as

Total charge = $0.75 × 6 + $1.25 × n

$14.50 = $0.75 × 6 + $1.25 × n

14.50 = 4.5 + 1.25n

1.25n = 14.5 - 4.5

1.25n = 10

n = 10 / 1.25

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3 years ago