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3 years ago

8x-9y=19 4x+y=-7 How Do I Do This Type Of Math

1 answer:

4 0

8x-9y=19
4x+y=-7
Multiply all terms of the 2nd by (9)===> 36x + 9y= 63

add (36x 9y= 63) to the 1st ===> 44x+0y = -44 ===> x=-1
replace x by this value in any of the equation & you'll get y=-3

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3. A bag has five blue marbles, seven red marbles and nine green marbles. Three marbles are drawn

Arte-miy333 [17]

Answer:

The probability is 9/266

Step-by-step explanation:

The first thing to do here is get the total number of marbles = 5 + 7 + 9 = 21 marbles

Now we are drawing the marbles without replacement, this means once a marble is drawn there is a decrease in the total number of marbles left.

The probability of drawing a green marble initially = number of green marbles/ total

number of marbles = 9/21 = 3/7

Now, we want to draw a blue marble

There are 5 blue marbles and we have already drawn one marble from the total. So the probability of drawing a blue marble would be 5/20 = 1/4

And lastly, another green marble

That would make 6 green marbles left and a total of just 19 left. So the probability at this point for green marbles = 6/19

Having and in probability means we multiply all

So this means the probability we are calculating is; 3/7 * 1/4 * 6/19 = 18/(28 * 19) = 9/(14 * 19) = 9/266

7 0

3 years ago

A wise man once said "300 reduced by 3 times my age is 138"

Nonamiya [84]

The equation is 138=300-3x
now solve by first subtracting 300 from each side: -162=-3x
divide each side by -3: x=54
The wise man is 54 years old

7 0

4 years ago

Use completing the square to solve x^2+6x=13

lara [203]

Answer:

x = -3 +/- square root(22)

Step-by-step explanation:

x = -b +/- square root(b^2 - 4ac) / 2a

ax^2 + bx + c = 0

these are both the quadratic formula but one is solved for the x and another for 0

a= 1

b= 6

c = -13

x= -6 +/- square root( 6^2 - 4(1)(13)) / 2(1)

x = -6 +/- sqrt( 36 + 52) / 2

x= -6 +/- sqrt (88) / 2

sqrt of 88 = 2 x sqrt (22)

divide 2 on each

x= -3 +/- sqrt (22)

8 0

3 years ago

What is the Answer to 3c-5=2c+5

lesya [120]

Your answer is c = 10

5 0

3 years ago

Read 2 more answers

Ann is adding water to a swimming pool at a constant rate. The table below shows the amount of water in the pool after different

N76 [4]

Answer:

(a) As time increases, the amount of water in the pool increases.

11 gallons per minute

(b) 65 gallons

Step-by-step explanation:

From inspection of the table, we can see that as time increases, the amount of water in the pool increases.

We are told that Ann adds water at a constant rate. Therefore, this can be modeled as a linear function.

The rate at which the water is increasing is the rate of change (which is also the slope of a linear function).

Choose 2 ordered pairs from the table:

$\textsf{let}\:(x_1,y_1)=(8, 153)$

$\textsf{let}\:(x_2,y_2)=(12,197)$

Input these into the slope formula:

$\textsf{slope}\:(m)=\dfrac{y_2-y_1}{x_2-x_1}=\dfrac{197-153}{12-8}=\dfrac{44}{4}=11$

Therefore, the rate at which the water in the pool is increasing is:

11 gallons per minute

To find the amount of water that was already in the pool when Ann started adding water, we need to create a linear equation using the found slope and one of the ordered pairs with the point-slope formula:

$y-y_1=m(x-x_1)$