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3 years ago

15x - 12y =13 30x +9y =4 whats the value of x

2 answers:

7 0

So assuming that x and y are the same value in both equations we can make the first equation negative (multiply the whole thing by -1) and get

-15x+12y=-13
we multiply it by 2 and get
-30x+24y=-26
we add this to the second equation
(30x+9y=4)+(-30x+24y=-26)
30x-30x+24y+9y=-22
or 33y=-22
divide both sides by 11
3y=-2
divide both sides by 3
y=-2/3

we subtitute it into the first equation
15x-12(-2/3)=13
15x-(-24/3)=13
15x+8=13
subtract 8 from both sides
15x=5
divide both sides by 5
3x=1
divide both sides by 3
x=1/3

so x=1/3
y=-2/3

monitta3 years ago

4 0

<u /> $\left \{ {{15x-12y=13\ \ | multiply\ by\ -2} \atop {30x+9y=4\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ }} \right. \\\\ \left \{ {{-30x+24y=-26} \atop {30x+9y=4}} \right.\\addition\ method\\\\33y=-22\ \ \ \ | divide\ by\ 33\\\\
y=-\frac{22}{33}\\\\
15x=13+12y\\\\
x=\frac{13+12y}{15}=\frac{13+12*(-\frac{22}{33})}{15}=\frac{13-\frac{264}{33}}{15}=\frac{13-8}{15}=\frac{1}{3}\\\\
Solution \ is\ x=\frac{1}{3}.
$

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Answer:

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4 years ago

Sum of 2 numbers is 42, and their difference is 8. What are the numbers?

Tems11 [23]

Answer:

25 , 17

Step-by-step explanation:

Let the unknown two numbers be x & y.

According to the question,

Sum of 2 numbers is 42.

x + y = 42 ⇒ ( 1 )

Their difference is 8.

x - y = 8 ⇒ ( 2 )

First let us find the value of x.

( 1 ) + ( 2 )

x + y + x - y = 42 + 8

2x = 50

Divide both sides by 2.

x = 25

And now let us find the value of y.

x + y = 42

25 + y = 42

y = 42 - 25

y = 17

Therefore, the two numbers are 25 , 17

Hope this helps you :-)

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8 0

3 years ago

Read 2 more answers

On a coordinate plane, a line has points (negative 2, negative 4) and (4, 2). Point P is at (0, 4). Which points lie on the line

NikAS [45]

Answer:

the correct options are:

(–1, 3), (–2, 2) and (–5, –1)

Step-by-step explanation:

Given that a line passes through two points

A(-2, -4) and B(4, 2)

Another point P(0, 4)

To find:

Which points lie on the line that passes through P and is parallel to line AB ?

Solution:

First of all, let us the find the equation of the line which is parallel to AB and passes through point P.

Parallel lines have the same slope.

Slope of a line is given as:

$m=\dfrac{y_2-y_1}{x_2-x_1}$

$m=\dfrac{2-(-4)}{4-(-2)} = 1$

Now, using slope intercept form ( $y = mx+c$ ) of a line, we can write the equation of line parallel to AB:

$y =(1)x+c \Rightarrow y = x+c$

Now, putting the point P(0,4) to find c:

$4 = 0 +c \Rightarrow c = 4$

So, the equation is $\bold{y=x+4}$

So, the coordinates given in the options which have value of y coordinate equal to 4 greater than x coordinate will be true.

So, the correct options are:

(–1, 3), (–2, 2) and (–5, –1)

8 0

3 years ago

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What if i=radical -1, what is the value of i^3

aleksklad [387]

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6 0

3 years ago

If x-12/x+36=0, what is the value of x

tatyana61 [14]

Answer:

Step-by-step explanation:

x - 12 / x + 36 = 0

Multiply both sides by x + 36

x - 12 = 0 ✖ (x + 36)

x - 12 = 0

Add 12 to both sides

x - 12 + 12 = 0 + 12

x = 12

I hope this was helpful, Please mark as brainliest

4 0

3 years ago

Read 2 more answers