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3 years ago

You haft too use elimination to solve this thank you

Mathematics

1 answer:

lakkis [162]3 years ago

5 0

Answer:

x=0, y=-2

Step-by-step explanation:

Because 9y appears twice in both equations, you can subtract the equations to eliminate the y variable so you can solve for x:

-7x + 9y = -18

-(4x + 9y = -18)

__________

-11x = 0

x = 0

Since we know x=0, then we plug it back into one of the equations to get the value of y:

-7x + 9y = -18

-7(0) + 9y = -18

0 + 9y = -18

9y = -18

y = -2

Therefore, x=0, and y=-2

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sin alpha = 7/25, alpha lies in quadrant ii, and cos beta = 2/5, beta lies in quadrant i. find cos(alpha-beta).

Ilia_Sergeevich [38]

Answer:

Therefore $\cos(\alpha-\beta)=\frac{48+7\sqrt{25}}{125}$

Step-by-step explanation:

Given values are

$\sin \alpha=\frac{7}{25}$

$\cos \beta=\frac{2}{5}$

$\sin^2x+\cos^2=1$

$\cos \alpha=\sqrt{1-\sin^2\alpha}$

$\cos \alpha=\sqrt{1-(\frac{7}{25})^2}$

$\cos \alpha=\sqrt{1-\frac{49}{625}}$

$\cos \alpha=\sqrt{\frac{576}{625}}$

$\cos \alpha=\frac{24}{25}$

$\sin \beta=\sqrt{1-\cos^2\beta}$

$\sin \beta=\sqrt{1-(\frac{2}{5})^2}$

$\sin \beta=\sqrt{1-\frac{4}{25}}$

$\sin \beta=\frac{\sqrt{21}}{5}$

$\cos(\alpha-\beta)=\cos\alpha\cos\beta+\sin\alpha\sin\beta$

$\cos(\alpha-\beta)=\frac{24}{25}\times\frac{2}{5}+\frac{7}{25}\times\frac{\sqrt{21}}{5}$

$\cos(\alpha-\beta)=\frac{48+7\sqrt{25}}{125}$

7 0

2 years ago

I NEED HELP UNDER 10 MINS PLEASE

ioda

Answer: The answer is C

7 0

2 years ago

Determine all the unknown values of the figure below.

Vanyuwa [196]

Answer:

F=10, S=26

Step-by-step explanation:

We know that the base is 24. Using that information, 10^2+24^2=26^2 which is a pythagorean triple

3 0

2 years ago

A video game has 25 levels. At level one, a player has 5 points. Each additional level increases the player's points by 10. If

ozzi

Answer:

B. (3,25)

Step-by-step explanation:

x = level of the video game

y = number of points

At level 1, a player has 5 points.

At level 2, the player has 5 + 10 = 15 points

Therefore, we can use the function notation this way:

f(x) = 5x + 10

The only ordered pair given that is from this function is:

B. (3,25)

f(3) = 5 * 3 + 10

f(3) = 15 + 10 = 25

The remaining three don't represent this function.

3 0

3 years ago

Triangle ABC is such that AB = 3cm , BC = 4cm , angle ABC = 120 and BAC = theta : Write down in terms of theta , and expression

lakkis [162]

1)inside the triangule is 180º .There are 3 angules, one with 120º, theta and
angle ACB, lets call it x.

x + theta + 120 = 180
x + theta= 180-120
x + theta= 60
x= 60- theta
angle ACB= 60- theta

8 0

3 years ago