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iren [92.7K]
4 years ago
15

i need help with number 7. its solving systems of equations by substitution. please show work!!! i need help

Mathematics
1 answer:
SCORPION-xisa [38]4 years ago
6 0
-4x+y=6
-5x-y=21

Solve for one side of either equation. I will use the first equation and solve for y.

-4x+y=6
+4x +4x

Y=4x+6
-5x-y=21

Now when you substitute, make sure to distribute properly including the easily missed negative.

-5x-(4x+6)=21
-5x-4x-6=21
-9x-6=21
-9x=27
X=27/-9

X=-3


Now that you know X, substitute to find Y.

Y=4(-3)+6
Y=-12+6

Y=-6

So your final answer is:
X=-3 Y=-6
(-3,-6)
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Highschool level trigonometry!!! Need help knowing step by step how to find answer!
Goshia [24]

Answer:

\theta \approx 82.34^\circ

Step-by-step explanation:

Please refer to the attached diagram. (Apologies if the shading or resolution is a bit off.)

So, we want to find θ.

Since we formed a right triangle, we can use right triangle ratios.

We know the measure of the adjacent side to θ and the hypotenuse.

Therefore, we will use the cosine ratio:

\displaystyle \cos(\theta)=\frac{\text{adjacent}}{\text{hypotenuse}}

The adjacent side is 2 and the hypotenuse is 15. By substitution:

\displaystyle \cos(\theta)=\frac{2}{15}

Now, we will take the inverse cosine of both sides. So:

\displaystyle \theta=\cos^{-1}\Big(\frac{2}{15}\Big)

Use a calculator. Hence:

\theta \approx 82.34^\circ

The angle between the ground and the ladder is about 82.34°.

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3 years ago
The Japanese 5 yen coin has a hole in the middle. If the diameter of the coin is 22 mm and the diameter of the hole is 5 mm, how
Yanka [14]

Answer:

4.4mm

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Diameter of coin = 22mm

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Therfroe the outer edge (circumference)

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The difference is

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7 0
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What is the chromatic number of the graph shown below?
Svetradugi [14.3K]

Answer:

the best answer would be 5

Step-by-step explanation:

5 0
4 years ago
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11:30 and 1:00
assuming that it is
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11:30 to 1:00 cannot be directly counted
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60 minutes in 1 hour so
11:30=11 hours and 30 mins
how far to 12 AM?
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then from 12 AM to 1 PM=1 hour so
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