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3 years ago

Please help. 6 points!

Mathematics

1 answer:

Brums [2.3K]3 years ago

8 0

Answer:the correct answer is b

Step-by-step explanation:

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Help me out please, im only typing this much because its making me...

Genrish500 [490]

Answer:

B. $x^{2} +2x-8$

Step-by-step explanation:

Here the best method to solve is by substituting the end values of the set in each option , otherwise it will a time consuming problem.

Now substitute x=-4 in all the options

A. $x^{2} -2x-8$

16+8-8=16>0

so out of option A and C option C is correct.

B. $x^{2} +2x-8$

16-8-8=0 which means for the values of x>-4 $x^{2} +2x-8$ is less than 0

Now substitute x=2 in all the options

A. $x^{2} -2x-8$

4-4-8=-8<0 . so option A and C both are incorrect.

B. $x^{2} +2x-8$

4+4-8=0 which means for the values of x<2 $x^{2} +2x-8$ is less than 0

Therefore the correct option is B

6 0

3 years ago

baherus [9]

Answer: see proof below

<u>Step-by-step explanation:</u>

Given: cos 330 = $\frac{\sqrt3}{2}$

Use the Double-Angle Identity: cos 2A = 2 cos² A - 1

$\text{Scratchwork:}\quad \bigg(\dfrac{\sqrt3 + 2}{2\sqrt2}\bigg)^2 = \dfrac{2\sqrt3 + 4}{8}$

Proof LHS → RHS:

LHS cos 165

Double-Angle: cos (2 · 165) = 2 cos² 165 - 1

⇒ cos 330 = 2 cos² 165 - 1

⇒ 2 cos² 165 = cos 330 + 1

Given: $2 \cos^2 165 = \dfrac{\sqrt3}{2} + 1$

$\rightarrow 2 \cos^2 165 = \dfrac{\sqrt3}{2} + \dfrac{2}{2}$

Divide by 2: $\cos^2 165 = \dfrac{\sqrt3+2}{4}$

$\rightarrow \cos^2 165 = \bigg(\dfrac{2}{2}\bigg)\dfrac{\sqrt3+2}{4}$

$\rightarrow \cos^2 165 = \dfrac{2\sqrt3+4}{8}$

Square root: $\sqrt{\cos^2 165} = \sqrt{\dfrac{4+2\sqrt3}{8}}$

Scratchwork: $\cos^2 165 = \bigg(\dfrac{\sqrt3+1}{2\sqrt2}\bigg)^2$

$\rightarrow \cos 165 = \pm \dfrac{\sqrt3+1}{2\sqrt2}$

Since cos 165 is in the 2nd Quadrant, the sign is NEGATIVE

$\rightarrow \cos 165 = - \dfrac{\sqrt3+1}{2\sqrt2}$

LHS = RHS $\checkmark$

4 0

3 years ago

Ann works at a store in the mall and earns a wage of 8 dollars an hour. She earns 10 dollars an hour is she works on the weekend

soldier1979 [14.2K]

Answer:

The Answer is $352

Step-by-step explanation:

8 times 24 = 192

10 times 16 = 160

192 + 160 = 352

6 0

3 years ago

CUSTOMERS AT A STORE

Sphinxa [80]

Answer:

480

Step-by-step explanation:

On Thursday there were 400 customers

1/5 of 400 =80

Increase Thursday's amount by 80

400+80 = 480

Friday has 480

6 0

2 years ago

Rebecca's buys some scarves that costs $5 each and 2 purses that cost $12 each. The cost of Rebecca's total purchase is $39. Wha

Illusion [34]

Scarves = 3

$$39 = 5n + 2(12)$
$$15 = 5n$
n = 3

8 0

2 years ago

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