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3 years ago

8

A student concluded that the inequality -3+2y<4x is equivalent to the inequality y>2x+3/2, as shown below. Describe and co

rrect the students error

1 answer:

svlad2 [7]3 years ago

4 0

Step-by-step explanation:

-3+2y<4x

then

2y< 4x+ 3 (add both sides with 3)

y < 2x +3/2 ( divide both sides by 2 that is positif and we do not change the sens < )

Hope you understand.

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Solve the system <br> 2x+2y+z=-2 <br> -x-2y+2z=-5<br> 2x+4y+z=0

drek231 [11]

The values of (x,y,z) are (3,-1,-2) , if the given are equations $2x+2y+z=- 2$ , $-x-2y+2z=-5$ and $2x+4y+z=0$ .

Step-by-step explanation:

The given is,

$2x+2y+z=- 2$ .......................................(1)

$-x-2y+2z=-5$ ......................................(2)

$2x+4y+z=0$ .........................................(3)

Step:1

Equation (2) is multiplied by -1 ( Eqn(2) × -1 )

$x+2y-2z=5$ .............................(4)

Subtract the equation (1) and (4)

$2x+2y+z=- 2$

$x+2y-2z=5$

( - )

$(2x-x)+(2y-2y)+(z+2z)=(-2-5)$

$x+3z=-7$ ......................(5)

Step:2

Equation (2) is multiplied by -2 ( Eqn(2) × -2)

$2x+4y-4z=10$ ........................(6)

Subtract equation (6) and (3),

$2x+4y-4z=10$

$2x+4y+z=0$

( - )

$(2x-2x)+(4y-4y)+(-4z-z)= (10-0)$

$-5z=10$

$z = - \frac{10}{5}$

z = -2

From the equation (5),

$x+3z=-7$

$x+(3)(-2)=-7$

$x = -7+6$

x = -1

From equation (1),

$2x+2y+z=- 2$

Substitute x and z values,

$(2)(-1)+2y+(-2)=-2$

$2y - 4=2$

$2y=4-2$

$2y=2$

$y=\frac{2}{2}$

y = 1

Step:3

Check for solution,

$-x-2y+2z=-5$

Substitute x,y and z values,

$-(-1)-(2)(1)+(2)(-2)=-5$

$1-2-4=-5$

-5 = -5

Result:

The values of (x,y,z) are (3,-1,-2) , if the given are equations $2x+2y+z=- 2$ , $-x-2y+2z=-5$ and $2x+4y+z=0$ .

8 0

3 years ago

just as a piece of wood that is 8 foot long he needs to cut pieces that are seven eighths of a foot long how many pieces will he

BlackZzzverrR [31]

He would make 7 peices

7 0

3 years ago

I'm not sure how to solve for x

Vikki [24]

Use the foil method to multiply out the expressions. Then solve for x by first combining like terms and then using inverse properties

8 0

3 years ago

Ace Cars says they will pay Jim a 10% commission on the sale price of each car. Budget Cars says they will pay him $500 per week

Arisa [49]

Answer:

$20,000

Step-by-step explanation:

You can quickly figure this by recognizing that the difference in commission must be the same as the base salary:

2.5%(car price) = $500

car price = $500/0.025 = $20,000

__

If you prefer, you can get there with equations.

At Job 1, the pay is ...

y = 10%×(car price)

At Job 2, the pay is ...

y = 7.5%×(car price)

Setting the equal (the two opportunities pay the same), we have ...

0.10(car price) = 500 +0.075(car price)

0.025(car price) = 500 . . . . . . . . subtract 0.075(car price)

car price = 500/0.025 = 20,000 . . . . divide by 0.025

Jim would have to sell a $20,000 car each week for the jobs to pay the same.

8 0

3 years ago

Help pleaseee 30 pointsss AM I CORRECT???

masha68 [24]

Answer:

Yes you are correct

Step-by-step explanation:

By doing that, you will get 8 which is the correct answer

4 0

2 years ago