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3 years ago

Two thirds of a number decreased by 27 is at least 9

Mathematics

1 answer:

11111nata11111 [884]3 years ago

3 0

Answer:

what?

Step-by-step explanation:

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HELP PLEASE I’LL MARK YOU BRAINLIEST IF YOU GET IT RIGHT

Darina [25.2K]

Well I know this is not linear becuase then the y-values would be going up by a constant number. So, B and C are gone. Personally, A looks a bid odd. So, If I were you I'd go with D.

Just my opinion, not 100%

4 0

2 years ago

Prove that sin3a-cos3a/sina+cosa=2sin2a-1

Sloan [31]

Answer:

$\frac{sin(3a)-cos(3a)}{sin(a)+cos(a)} =2sin(2a)-1$

Step-by-step explanation:

we are given

$\frac{sin(3a)-cos(3a)}{sin(a)+cos(a)} =2sin(2a)-1$

we can simplify left side and make it equal to right side

we can use trig identity

$sin(3a)=3sin(a)-4sin^3(a)$

$cos(3a)=4cos^3(a)-3cos(a)$

now, we can plug values

$\frac{(3sin(a)-4sin^3(a))-(4cos^3(a)-3cos(a))}{sin(a)+cos(a)}$

now, we can simplify

$\frac{3sin(a)-4sin^3(a)-4cos^3(a)+3cos(a)}{sin(a)+cos(a)}$

$\frac{3sin(a)+3cos(a)-4sin^3(a)-4cos^3(a)}{sin(a)+cos(a)}$

$\frac{3(sin(a)+cos(a))-4(sin^3(a)+cos^3(a))}{sin(a)+cos(a)}$

now, we can factor it

$\frac{3(sin(a)+cos(a))-4(sin(a)+cos(a))(sin^2(a)+cos^2(a)-sin(a)cos(a)}{sin(a)+cos(a)}$

$\frac{(sin(a)+cos(a))[3-4(sin^2(a)+cos^2(a)-sin(a)cos(a)]}{sin(a)+cos(a)}$

we can use trig identity

$sin^2(a)+cos^2(a)=1$

$\frac{(sin(a)+cos(a))[3-4(1-sin(a)cos(a)]}{sin(a)+cos(a)}$

we can cancel terms

$=3-4(1-sin(a)cos(a))$

now, we can simplify it further

$=3-4+4sin(a)cos(a))$

$=-1+4sin(a)cos(a))$

$=4sin(a)cos(a)-1$

$=2\times 2sin(a)cos(a)-1$

now, we can use trig identity

$2sin(a)cos(a)=sin(2a)$

we can replace it

$=2sin(2a)-1$

so,

$\frac{sin(3a)-cos(3a)}{sin(a)+cos(a)} =2sin(2a)-1$

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2 years ago

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The sum of two consecutive integers is 201 find the integers

telo118 [61]

100 and 101

the two integers are n and n+1. this means that 2n+1=201. n=100 and n+1=101

8 0

2 years ago

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What is the value of the expression below when x equals 5?<br><br> 16 + 10x

Inessa05 [86]

Answer:

Step-by-step explanation:

Plug in 5 for x

16 + 10(5)

16 + 50 = 66

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2 years ago

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Which of the following lines is perpendicular to the equation y= -2x+8

Varvara68 [4.7K]

Answer:

Step-by-step explanation:iii

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2 years ago