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3 years ago

Error analysis

Mathematics

2 answers:

Bas_tet [7]3 years ago

8 0

2(2x-1) + 2(3x)=4x-2+6x = 10x - 2 & not =10x-1

Aliun [14]3 years ago

3 0

One side (l) = 2x-1
other side (w) = 3x

perimiter = all of the sides added together

perimiter = 2l + 2w

perimiter = 2(2x-1) + 2(3x)

2(2x) - 2(1) + 2(3x) = 4x - 2 + 6x

perimiter = 10x - 2

The previous statement is incorrect because the student did not distribute the 2 onto the -1.

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A chef plans to mix 100% vinegar with Italian dressing. The Italian dressing contains 12%

Hitman42 [59]

Answer:

Amount of vinegar. 100% : 20 milliliters

Amount of Italian dressing: 140 milliliters

Step-by-step explanation:

Let's call A the amount of vinegar. 100%

Let's call B the amount of Italian dressing . 12% vinegar

The resulting mixture should have 23% vinegar, and 160 milliliters.

Then we know that the total amount of mixture will be:

$A + B = 160$

Then the total amount of pure antifreeze in the mixture will be:

$A + 0.12B = 0.23 * 160$

$A + 0.12B = 36.8$

Then we have two equations and two unknowns so we solve the system of equations. Multiply the first equation by -1 and add it to the second equation:

$-A -B = -160$

$A + 0.12B = 36.8$

--------------------------------------

$-0.88B = -123.2$

$B = \frac{-123.2}{-0.88}$

$B = 140\ milliliters$

We substitute the value of B into one of the two equations and solve for A.

$A + 140 = 160$

$A = 20\ milliliters$

7 0

3 years ago

Solve the equation. Then check your solution. – two-fifths + a = One-fifth a. Three-fifths c. StartFraction 3 Over 10 EndFractio

VLD [36.1K]

Answer:

a = Negative one-fifth

Step-by-step explanation:

The given equation is :

$\dfrac{2}{5}+a=\dfrac{1}{5}$

We need to find the value of a.

Subtract 2/5 from both sides.

$\dfrac{2}{5}+a-\dfrac{2}{5}=\dfrac{1}{5}-\dfrac{2}{5}\\\\a=\frac{1}{5}-\frac{2}{5}\\\\a=\dfrac{-1}{5}$

So, the correct answer is Negative one-fifth. Hence, the correct option is (b).

5 0

3 years ago

Please do them step by step;

ELEN [110]

For the first one c-9=(2)(4)+6
You are gonna multiply 2 and 4 first, 2*4=8. Now you have c-9=8+6. 8+6=14. So now the equation is c-9=14. Now we are going to add 9 to both sides. So c=23
For the second equation 10+y=90. We are going to subtract 10 from both sides. So, y=80.
Third, add 4 to both sides. a=10.
Fourth, subtract 8 from both sides. d=-9
Fifth, 5+2(3+4)=-x.
First we are going to add 3 and 4. 3+4=7. 5+2(7)=-x. Next we are going to multiply 2 and 7. 2*7=14. 5+14=-x. 5+14=19. So our equation is 19=-x. Next we are going to multiply both sides by -1. Making our final equation x=-19.
c=23
y=80
a=10
d=-9
x=-19
I hope that helps, if you need any further explanation just ask.

3 0

3 years ago

Need help with this question , pls help

notka56 [123]

Answer:

A = 80g B = 200g

Step-by-step explanation for A:

First, you would find what the serving size is divided by to get the number of people needed to feed 6/3 = 2. Then take that number (3) and divided it by the fish (240g) to get 240/3 = 80.

Step-by-step explanation for B:

You will first need to find how much butter goes into ONE pie by dividing 80 by 6 which is 1.33333333333333. Then do 1.333333333333333 times the number of people to feed (15) to get 200.

8 0

2 years ago

A store is advertising a sale with 15% off all prices in the store. Sales tax is 8%. Which equation will correctly determine the

hoa [83]

I think the answer is c beacause you have to multiply to get the answer

4 0

3 years ago