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kap26 [50]
3 years ago
5

All questions to be solved using linear combination.

Mathematics
1 answer:
monitta3 years ago
8 0
1)
I:x-y=-7
II:x+y=7

add both equations together to eliminate y:
x-y+(x+y)=-7+7
2x=0
x=0

insert x=0 into II:
0+y=7
y=7

the solution is (0,7)

2)
I: 3x+y=4
II: 2x+y=5

add I+(-1*II) together to eliminate y:
3x+y+(-2x-y)=4+(-5)
x=-1

insert x=-1 into I:
3*-1+y=4
y=7

the solution is (-1,7)

3)

I: 2e-3f=-9
II: e+3f=18

add both equations together to eliminate f:
2e-3f+(e+3f)=-9+18
3e=9
e=3

insert e=3 into I:
2*3-3f=-9
-3f=-9-6
-3f=-15
3f=15
f=5

the solution is (3,5)

4)
I: 3d-e=7
II: d+e=5

add both equations together to eliminate e:
3d-e+(d+e)=7+5
4d=12
d=3

insert d=3 into II:
3+e=5
e=2

the solution is (3,2)

5)
I: 8x+y=14
II: 3x+y=4

add I+(-1*II) together to eliminate y
8x+y+(-3x-y)=14-4
5x=10
x=2

insert x=2 into II:
3*2+y=4
y=4-6
y=-2

the solution is (2,-2)
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What is the value of this expression?<br> 5x (8 – 3) + 2
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Step-by-step explanation:

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Hope that helps!

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3 years ago
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Wich of rhe following representents the formula thst could be used to find the height of the cone
VLD [36.1K]

Answer:

Cone volume = [PI * radius ^ 2 * height] / 3   therefore,

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Step-by-step explanation:


5 0
3 years ago
If the ratio of y to x is equal to 3 and the sum of y and x is 80, what is value of y
Rus_ich [418]

Answer:

y = 60

Step-by-step explanation:

<h3>Step 1: Make sense of the given</h3>

"The ratio of y to x is 3"

This means that, y\div x=3

"The sum of y and x is 80"

This means,  x+y=80

<h3>Step 2: Make use of the facts</h3>

If y\div x=3, then y = (3*x).

We can plug this into the other equation by substitution:

x + (3 * x)=80

This simplifies to:

4x = 80

Which we can solve out and get:
x=20.

<h3>Step 3: Plug and Chug</h3>

We solved for x, but we need the value of y.

So, we go back to the equation we first derived: "y = (3*x)".

And now we substitute the value of x, into this.

y = (3 * (20))

By solving this out, we get:
y=60

So, the value of y is 60.

3 0
1 year ago
What is the ratio of girls to boys if there are 15 girls and 5 boys?
WINSTONCH [101]
The answer is 15 : 5

because In mathematics, a ratio is a relationship between two numbers indicating how many times the first number contains the second. For example, if a bowl of fruit contains eight oranges and six lemons, then the ratio of oranges to lemons is eight to six (that is, 8:6, which is equivalent to the ratio 4:3).
And you said girls : boys

That means 15 : 5 or 15 to 5
8 0
3 years ago
Read 2 more answers
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