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Serga [27]
4 years ago
5

The store has sold 90 notebooks which is 20% of all the notebooks they had how many notebooks did the store have at first

Mathematics
1 answer:
kirill115 [55]4 years ago
4 0
90 is 20% so

90 x 5 = 450 note books
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Graph the piecewise function given below.
Kazeer [188]

Answer:

this may help you.look it once.

8 0
3 years ago
Find sin20 if sin 0 = 3; 90° < 0 < 180°
Alex777 [14]

Answer:

\sin 2 \theta = -\dfrac{4\sqrt 5}{9}

Step-by-step explanation:

\text{Given that,}\\\\~~~~~~\sin \theta = \dfrac 23\\\\\implies \sin^2 \theta = \left( \dfrac 23 \right)^2\\\\\implies 1- \cos^2 \theta = \dfrac 49 \\\\\implies \cos^2 \theta = 1 - \dfrac 49 \\\\\implies \cos^2 \theta = \dfrac 59\\\\\implies \cos \theta = \pm\sqrt{\dfrac 59} \\\\\implies \cos \theta = \pm \dfrac{\sqrt 5 }3\\\\\text{Since}~ 90^\circ < \theta < 180^{\circ},~\text{the angle lies in 2nd quadrant}\left(\cos \theta ~\text{is negative}\right).\\\\

\text{So,}~ \cos \theta = - \dfrac{\sqrt 5 }{3}\\\\\text{Now,}\\\\\sin 2\theta = 2\sin \theta \cos \theta \\\\\\~~~~~~~~=2 \cdot \dfrac 23 \cdot \left( -\dfrac{\sqrt 5}{3} \right)\\\\\\~~~~~~~~=-\dfrac{4\sqrt 5}{9}

\textbf{Quadrant rule:}\\\\

6 0
2 years ago
Find the measure of angle CED in the figure below. Enter only the number.
nikdorinn [45]

Answer:

∠ CED = 58°

Step-by-step explanation:

∠ CED and ∠ AED are adjacent angles and sum to 180° , then

∠ CED + 122° = 180° ( subtract 122° from both sides )

∠ CED = 58°

6 0
2 years ago
Read 2 more answers
Please answer these with lots of detail. I want to be able to understand the topic and material well.
IRISSAK [1]

Step-by-step explanation:

Q3

(a) If 0 < |x − 1| < δ, then |f(x) − 2| < 2

What this means is, how far can x stray from the x=1 line such that f(x) stays within 2 units of the y=2 line (0 < f(x) < 4).

If we move 2 units left of x=1, we get f(x) = 4.

If we move about 3.5 units right of x=1, we get f(x) = 4.

Therefore, δ can't be more than 2.

(b) If 0 < |x| < δ, then |f(x) − 3| < 1

What this means is, how far can x stray from the x=0 line such that f(x) stays within 1 unit of the y=3 line (2 < f(x) < 4).

If we move 1 unit left of x=0, we get f(x) = 4.

If we move 1 unts right of x=0, we get f(x) = 2.

Therefore, δ can't be more than 1.

Since f(x) isn't continuous within this domain, we can't conclude that the limit exists.

Q4

(a) Yes.  If δ = 0.25, then 0.75 < x < 1.25, and f(x) > 200.

(b) No.  f(1) = 300, so even if δ = 0, f(x) will be less than 400.

(c) Yes.  If δ ≈ 0.1, then 0.9 < x < 1, and f(x) > 450.

6 0
4 years ago
Help please? not sure about this
zimovet [89]

9514 1404 393

Answer:

  72 kph

Step-by-step explanation:

The first sentence tells you the speeds are proportional. So, you can write the proportion ...

  kph/mph = 120/75 = x/45

Multiplying by 45 gives x:

  x = (45)(120/75) = 72

72 kph is 45 mph.

8 0
3 years ago
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