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harina [27]
3 years ago
11

Solve x2 - 8x = 3 by completing the square. Which is the solution set

Mathematics
1 answer:
Simora [160]3 years ago
3 0

Answer:

4\pm\sqrt{19}

Step-by-step explanation:

Move everything to left side

x^{2} -8x -3 =0

Now to solve this square equation we need to find Descriminant

D=b^{2} -4ac=64+12=76

As Descriminant D is greater than 0 then we have 2 solutions which we can calculate by this formula

x_{1,2}=\frac{-b\pm\sqrt{D}}{2a} =\frac{8\pm2\sqrt{19}}{2}=4\pm\sqrt{19}

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Confused beyond confused
Maru [420]
So this does sound quite confusing at first, but let's try to pull the numbers out of this word problem first.

There is a maximum of 1,000 tickets.
The tickets are $8 before and $10 on the day of the show.
They need to sell at least $7,500 worth of tickets.

A) We want to write a system of inequalities, so we translate this into mathy language.

Since the maximum is 1,000, there are no more than 1,000 tickets. Another way of writing this is T \leq 1000.

The total price of the tickets must be at least $7,500, (or no less than $7,500). We can write this as C \geq 7500.

Now, the key is writing this with the prices of the tickets we are given. Forget about the variables we just named.

Let's say the number of tickets purchased before the show is x, and the number on the day-of is y.

The total number of these tickets can't be more than 1,000, right?

So we can write x+y \leq 1000.

If you sell x tickets, since you make $8 for every ticket, you make 8x dollars. If you sell y tickets, since you make $10 for every ticket, you make 10y dollars.

And we need at least $7,500, so we can write 8x+10y \geq 7500.

These two inequalities model the situation: x+y \leq 1000 and 8x+10y \geq 7500. Don't forget to state that x is the number of tickets sold before the show, and y is the number on the day-of.

B) The club sold 550 tickets before the show, meaning x is 550. Remember, each ticket purchased then costs $8, so thus far, the club made $550<span>⋅8 = $4,400. 

They can sell up to 1,000 – 550 tickets today, so 450 more tickets. Each ticket sold today costs $10, so they can make $450</span><span>⋅10 = $4,500.

They need to make at least $7,500. They have already made $4,400, and they can make up to $4,500 more, so they can make up to $8,900, which is more than $7,500. So yes, they can meet their goal.</span>
6 0
3 years ago
Simplify the following: (r+s-t)-(r-s+t)
ArbitrLikvidat [17]
R+s-t-(r-s+t)

=2s-t is the answer



People think this answer would be just =2s but I have verified with an online calculator and the answer that textbooks look for regarding this is 2s-t

You would assume you would go r-r and thats 0 so no r's

you would say s-(-s) makes it plus and theres 2s

and you would say -t -(+t) is -t 

that's why the answer is 2s-t

At first I also did t-(+t) and thought it would be no t's but the answer is in fact 2s-t 
4 0
4 years ago
Find the volume of the cylinder
julsineya [31]

The volume of the cylinder is

62.83 units³

3 0
3 years ago
Read 2 more answers
LOL 3 more to gooo . find the value of x
garri49 [273]

Answer:

17

Step-by-step explanation:

These two angles add up to 180, so we can set up an equation. 5x-23+7x-1=180. Now we combine like variables, getting 12x-23-1=180. We add 23 to both sides, and get 12x-1=203. Then we add 1 to both sides, getting 12x=204. Finally we divide by 12 on both sides, with our result as x=17.

8 0
3 years ago
A trapezoid has a base of 4.5 inches, a height of 6 inches, and an area of 21 square inches. The equation below can be used to d
Westkost [7]

Answer:

2.5in

Step-by-step explanation:

Given parameters;

  Base = 4.5inches

   Height = 6inches

    Area  = 21in²

Unknown:

b₂ = ?

Solution:

 Formula for finding the area of a trapezium;

         A = \frac{1}{2}(b_{1} + b_{2}  ) x h

     Input the parameters and solve for b₂;

      21  =  \frac{1}{2}(4.5+ b_{2}  ) x 6

   

       21 = 3(4.5 + b₂)

       21 = 13.5 + 3b₂

      21 - 13.5 = 3b₂

     b₂ = 2.5in

8 0
4 years ago
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