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Firlakuza [10]
3 years ago
15

I'd really appreciate some help on these questions, I'm really struggling

Mathematics
1 answer:
nikklg [1K]3 years ago
6 0
We can use linear combinations of the equations to eliminate variables.

3x - 4y = 1
-2x + 3y = 1

To eliminate y we'll make the linear combination of 3 times the first equation minus four times the second. 

9x - 12y = 3
-8x + 12y = 4

Adding,
x = 7

We could solve for y directly but let's use another linear combination, twice the first plus three times the second:

2(3x - 4y) + 3(-2x + 3y)= 2(1)+3(1)

y = 5

Check: 3(7)-4(5)=1 good.   -2(7)+3(5)=1 good.

Q18 Answer: (7,5)

y = -3x + 5
5x - 4y = -3

4y +1(5x - 4y) = 4(-3x + 5) + 1(-3)

5x = -12x + 20 -3

17 x = 17

x = 1
y = -3(1) + 5 = 2
Check: 5(1) - 4(2) = -3 good

Q19 Answer (1,2)

6x + 5y = 25
x = 2y + 24
6x = 12y + 144
5y = 25 - 12y - 144
17y = -119
y = -119/17= -7
x = 2y+24= 10
Check: 6(10)+5(-7)=25 good   2y+24=2(-7)+24=10=x good

Q20 Answer (10,-7)


3x + y = 18
-7x + 3y = -10
9x  + 3y = 54
9x - -7x = 54 - -10
16x = 64
x=4
y = 18 -3x = 18-12=6

Check: 3(4)+6=18 good,  -7(4)+3(6)=-10 good

Q21 Answer: (4,6)

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Can you help me out on this one
Bad White [126]

Answer:

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Step-by-step explanation:

6 0
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1. Consider drawing a single card from a well shuffled 52-card deck. Let E1 be an event of getting a heart card and E2 be an eve
Paraphin [41]
<span>1) Find P(E1UE2)
E1 probability= 1/2</span>
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<span>The face cards are: Jacks, Queens, and <span>Kings. There are four suits, so in each suit there are one jack, one queen and one king. The probability is 3 x 4= 12 divided by the total number of cards.

2)</span></span><span>the probability of drawing a blue ball on the first draw: 4 /10
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6 0
3 years ago
Express the radical using the imaginary unit, i
Kipish [7]

Answer:

7i.

Step-by-step explanation:

Note : The given expression must be \sqrt{-49}.

We have to write this radical value in the imaginary value.

The given value can be rewritten as

\sqrt{-49}=\sqrt{49\times (-1)}

\sqrt{-49}=\sqrt{49}\times \sqrt{-1}    [\because \sqrt{ab}=\sqrt{a}\sqrt{b}]

\sqrt{-49}=7\times i    [\because \sqrt{-1}=i]

\sqrt{-49}=7i

Therefore, the required expression is 7i.

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