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3 years ago

Evaluate the expression 2(2x-3y)-5xy where x=-2 and y=-1

Mathematics

1 answer:

icang [17]3 years ago

8 0

Answer:

-12

Step-by-step explanation:

2 (2x-3y)-5xy

4x-6y-5xy

4(-2)-6(-1)-5*-2*-1

-8+6-10

-12

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Cos x if sin x cot x =5

Brrunno [24]

Answer:

cos x = 5

Step-by-step explanation:

$= > sinx.cotx = 5 \\ \\ = > \cancel{sinx}. \frac{cosx}{ \cancel{sinx}} = 5 \\ \\ = > cosx = 5$

8 0

4 years ago

2. (-5+ 6n to the 3rd power) + (1- 2n to the 2nd power)

Alja [10]

I think it would -4 + 6n to the power of 3 - 2n to the power of 2. I could be wrong. If so, you can report it as an error or something.

4 0

4 years ago

Find sin(a+B)

diamong [38]

Answer:

Cos A=5/13

we have

Cos² A= $1-Sin ²A$

25/169=1-Sin²A

sin²A=1-25/169

sin²A=144/169

Sin A= $\sqrt{144/169}=12/13$

again

Tan B=4/3

P/b=4/3

p=4

b=3

h= $\sqrt{3²+4²}=5$

Now

Sin B=p/h=4/5

in IV quadrant sin angle is negative so

Sin B=-4/5

CosB=b/h=3/5

Now

Sin(A+B):sinAcosB+CosAsinB

now 

substitute value

Sin(A+B):12/13*3/5+5/13*(-4/5)=36/65-4/13

=16/65 is a required answer

6 0

3 years ago

A person in the audience of a reality show has an 11% chance of winning free movie tickets. What is the chance that a person in

olya-2409 [2.1K]

100%=all
all-change of wining=change of not winning
100%-11%=89% of not winning

probabilit is 89/100 that they dont win

8 0

4 years ago

*A number consisting of two digits is three times the sum of its digits. If 45 is added

stich3 [128]

Answer: The number is 27

The system of equations is: 7x - 2y = 0

-9x + 9y = 45

Step-by-step explanation:

Let x represent the number in the tens place and y represent the number in the ones place. x y

Then 10x + y = 3(x + y)

When the digits are reversed: 10y + x = 10x + y + 45

Simplify each of the above equations and then create a system of equations:

10x + y = 3x + 3y → 7x - 2y = 0

10y + x = 10x + y + 45 → -9x + 9y = 45

9( 7x - 2y = 0) → 63x - 18y = 0

2(-9x + 9y = 45) → -18x + 18y = 90

45x = 90

x = 2

Input x = 2 into either equation to solve for y:

7x - 2y = 0

7(2) - 2y = 0

14 = 2y

7 = y

8 0

3 years ago

Read 2 more answers