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Artemon [7]
3 years ago
9

Slove by using elimination 3x+7y=27 -3x+y=21

Mathematics
1 answer:
tankabanditka [31]3 years ago
8 0

Answer:

x = -5

y = 6

Step-by-step explanation:

3x + 7y = 27      --------------(I)

-3x + y = 21        -----------(II)

Add equation (I) & (II) and so x will be eliminated and we can find the value of y.

(I)      3x + 7y = 27    

(II)    <u> -3x + y = 21  </u>      {add}

                8y = 48

                   y = 48/8

                   y = 6

Plugin y = 6 in equation (I)

3x +7*6 = 27

3x + 42 = 27

       3x = 27 - 42

       3x = -15

         x = -15/3

x = -5

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In the figure to the right, can you conclude that triangle GHI is congruent to triangle KJI? Justify your reasoning.
inessss [21]

Answer:

No

Step-by-step explanation:

You cannot conclude that ΔGHI is congruent to ΔKJI, because although you can see/interpret that there all the angles are congruent with one another, like with vertical angles (∠GIH and ∠KIJ) and alternate interior angles (∠H and ∠J, ∠G and ∠K), we don't know the side lengths.

All the angles could be congruent, but the sides might be different. For example, ΔGHI might be a bigger triangle than ΔKJI, which could make them similar to one another, but not congruent.

For something to be congruent to another, everything must be exactly the same.

7 0
3 years ago
Factor completely.<br> x² - 3x² - 4
Ber [7]

Answer:

-2(x^2+2)

Step-by-step explanation:

1. x^2-3x^2-4
= -2x^2-4
2. -2(x^2+2) factor completely :)

7 0
2 years ago
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Archy [21]

Answer:

the total cost would be $15,900

Step-by-step explanation:

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5 0
3 years ago
6. MONEY Len bought a $24.99 pair of pants
tatuchka [14]

Answer:

$2.06 tax

Step-by-step explanation:

$24.99 pants

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24.99 + tax = 27.05

tax = 27.05 - 24.99

27.05 - 24.99 = 2.06

7 0
3 years ago
dale is driving to Miami. suppose that the distance (in miles) is a linear function of his total driving time (in minutes). dale
nexus9112 [7]
Considering there is a function (relationship) and that it is linear, the distance will change proportionally to time constantly. In other words, we are taking the speed to be constant throughout the journey.
If we let:
t = time (min's) driving
d = distance (miles) from destination
Then we can represent the above information as:
t = 40: d = 59
t = 52: d = 50
If we think of this as a graph, we can think of the x-axis representing time and the y-axis representing the distance to the destination. Being linear, the function will be a line, i.e. it will have a constant gradient. If you were plot the two points inferred from the information and connect the two dots, you will get a declining line (one with a negative gradient) representing the inversely proportional relationship or equally, the negative correlation between the time driving and the distance to the destination. The equation of this line will be the linear function that relates time and the distance to the destination. To find this linear function, we do as follows:

Find the gradient (m) of the line:
m = Δy/Δx
In this case, the x-values are t-values and our y-values are d-values, so:
Δy = Δd
= 50 - 59
= -9
Δx = Δt
= 52 - 40
= 12
m = -9/12 = -3/4
Note: m is equivalent to speed with units: d/t

Use formula to find function and rearrange to give it in the desired format:
y - y₁ = m(x - x₁)
d - 50 = -3/4(t - 52)
4d - 200 = -3t + 156
4d + 3t - 356 = 0

Let t = 70 to find d at the time:
4d + 3(70) - 356 = 0
4d + 210 - 356 = 0
4d - 146 = 0
4d = 146
d = 73/2 = 36.5 miles

So after 70 min's of driving, Dale will be 36.5 miles from his destination.
3 0
3 years ago
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