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Vilka [71]
3 years ago
13

Can anyone please help me with this? i need a step by step explanation please! very appreciated:)

Mathematics
2 answers:
d1i1m1o1n [39]3 years ago
8 0

Answer:

x=8 and y=31

Let's solve your system by substitution.

y=5x−9;y=3x+7

Step: Solve y=5x−9for y:

y=5x−9

Step: Substitute5x−9foryiny=3x+7:

y=3x+7

5x−9=3x+7

5x−9+−3x=3x+7+−3x (Add -3x to both sides)

2x−9=7

2x−9+9=7+9(Add 9 to both sides)

2x=16

2x/2=16/2 (Divide both sides by 2)

x=8

Step: Substitute 8 for x in y=5x−9:

y=5x−9

y=(5)(8)−9

y=31 (Simplify both sides of the equation)

Answer:

x=8 and y=31

NOTE: <u><em>Please give the brainly to the first answer</em></u>

<u><em /></u>

HOPE THIS HELPS <33333

-Silver

EastWind [94]3 years ago
5 0

Answer:

Step-by-step explanation:

x and y are variables. That means they represent numbers that are unknown. When we solve for x or y, we are trying to find what number the variable represents.

Y is a number that equals both 5x-9 and 3x+7. If it is a number, it can only have one value, so we can say that 5x-9 and 3x+7 have the same value.

In other words, 5x-9 = 3x+7.

Another way of thinking about this step is substitution. y=3x+7, so in the equation y=5x-9, we can replace the y with 3x+7. It will give 3x+7 = 5x-9.

In either case, we have this new equation

5x-9 = 3x+7.

From here it's just simple algebra- subtract 3x from each side

2x -9 = 7

and add 9 to each side

2x = 16

and divide each side by 2.

x = 8.

All these steps work because if two things equal each other, when you do the same thing to both of them (such as add 9), the new values will still equal each other.

Now that we know that x = 8, we can take one of the original equations

y=5x-9

and put 8 in for x.

y=5*(8) -9.

If x represents the value 8, we can obviously switch out x for 8.

Now simplify

y=40 -9

y = 31

Now we know that x = 8 and y = 31.

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2) Radius = 1.5 cm Height = 6 cm
tino4ka555 [31]

Answer:

42.41 cm^3

Step-by-step explanation:

4 0
3 years ago
Mr. Shipley is in charge of a school trip. 317 students will go on the trip. Thhe school had seven buses and one van. If the van
sergey [27]

Answer:

<u>44 </u>students will ride on each bus.

Step-by-step explanation:

Given:

Mr. Shipley is in charge of a school trip.

317 students will go on the trip.

The school had seven buses and one van.

If the van can haul nine students.

Now, to find the number of students who will ride on each bus.

Total students who will go on trip = 317.

So, we deduct the nine students of van from total students.

317-9=308.

Thus, there are 308 students remaining for riding on the seven buses.

Now, to get the number of students that will be riding on each bus we divide 308 remaining students by number of buses:

308\div 7

=44.

Therefore, 44 students will ride on each bus.

6 0
3 years ago
PLEASE HELP QWQ AsAp with these 4 questions
den301095 [7]

Answer:

Step-by-step explanation:

I can't believe I'm doing this for 5 points, but ok!

For the first 3, we are going to multiply to find the value of that 3 x 3 matrix by picking up the first 2 columns and plopping them down at the end and then multiplying through using the rules for multiplying matrices:

\left[\begin{array}{ccccc}7&4&6&7&4\\-4&8&9&-4&8\\1&8&7&1&8\end{array}\right]  and from there find the sum of the products of the main axes minus the sum of the products of the minor axes, as follows (I'm not going to state the process in the next 2 problems, so make sure you follow it here. This is called the determinate. The determinate is what you get when you evaluate or find the value of a matrix. Just so you know):

(7*8*7)+(4*9*1)+(6*-4*8)-[(1*8*6)+(8*9*7)+(7*-4*4)] which gives us:

392 + 36 - 192 - [48 + 504 - 112] which simplifies to

236 - 440 which is -204

On to the second one:

\left[\begin{array}{ccccc}-8&-4&-1&-8&-4\\1&7&-3&1&7\\8&9&9&8&9\end{array}\right] and multiplying gives us

(-8*7*9)+(-4*-3*8)+(-1*1*9)-[(8*7*-1)+(9*-3*-8)+(9*1*-4)] which gives us:

-504 + 96 - 9 - [-56 + 216 - 36] which simplifies to

-417 - 124 which is -541, choice c.

Now for the third one:

\left[\begin{array}{ccccc}-2&-2&-5&-2&-2\\2&7&-3&2&7\\8&9&9&8&9\end{array}\right] and multiplying gives us

(-2*7*9)+(-2*-3*8)+(-5*2*9)-[(8*7*-5)+(9*-3*-2)+(9*2*-2)] which gives us:

-126+48-90-[-280+54-36] which simplifies to

-168 - (-262) which is 94, choice c again.

Now for the last one. I'll show you the set up for the matrix equation; I solved it using the inverse matrix. So I'll also show you the inverse and how I found it.

\left[\begin{array}{cc}-4&-5&\\-6&-8\\\end{array}\right] \left[\begin{array}{c}x\\y\\\end{array}\right] = \left[\begin{array}{c}-5\\-2\\\end{array}\right] and I found the inverse of the 2 x 2 matrix on the left.

Find the inverse by:

* finding the determinate

* putting the determinate under a 1

* multiply that by the "mixed up matrix (you'll see...)

First things first, the determinate:

|A| = (-4*-8) - (-6*-5) which simplifies to

|A| = 32 - 30 so

|A| = 2; now put that under a 1 and multiply it by the mixed up matrix. The mixed up matrix is shown in the next step:

\frac{1}{2}\left[\begin{array}{cc}-8&5\\6&-4\end{array}\right]  (to get the mixed up matrix, swap the positions of the numbers on the main axis and then change the signs of the numbers on the minor axis). Now we multiply in the 1/2 to get the inverse:

\left[\begin{array}{cc}-4&\frac{5}{2}\\3&-2\\\end{array}\right] Multiply that inverse by both sides of the equation. This inverse "undoes" the matrix that's already there (like dividing the matrix that's already there by itself) which leaves us with just the matrix of x and y. Multiply the inverse matrix by the solution matrix:

\left[\begin{array}{c}x&y\end{array}\right] =\left[\begin{array}{cc}-4&\frac{5}{2} \\3&-2\end{array}\right] *\left[\begin{array}{c}-5&-2\\\end{array}\right] and that right side multiplies out to

x = 20 - 5 which is

x = 15 and

y = -15 + 4 which is

y = -11

(It works, I checked it)

7 0
3 years ago
Mr. Nanez collects quitars. He has 4 black guitars, 2 white quitars and 9 brown quitars, What is is ratio of black guitars to al
aksik [14]

Answer:

4:15

Step-by-step explanation:

Sum of all quitars: 2+4+9=15

4 black quitars to 15 quitars

4:15

5 0
3 years ago
Enter &lt;, &gt;, or = to make the<br> statement true.<br> .320 [?] .051
koban [17]

Answer: .320 is greater than .051 (use the > sign)

Step-by-step explanation:

too lazy to explain, but yes

3 0
3 years ago
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