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natulia [17]
3 years ago
15

7x + 2y = 4

Mathematics
2 answers:
Vinil7 [7]3 years ago
5 0

7x + 2(x + 1) = 4 \\ 7x + 2x + 2 = 4 \\ 9x  + 2 = 4 \\ 9x = 2 \\ x =  \frac{2}{9}  \\  \\ y =  \frac{2}{9}  + 1 =  \frac{11}{9}  \\ ( \frac{2}{9}  \:  \frac{11}{9} )
abruzzese [7]3 years ago
3 0
It’s B.

y=x+1

7x+2(x+1)=4

y=x+1
9x+2=4

Subtract 4-2 from the second equation.

The we have y=x+1

9x=2

x=2/9

Then plug in x into the other equation bc now we know it!

y=2/9+1

Which is 11/9

I hope this helps!!!
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MATH - look at the picture and i will mark you as brainliset if you answer correctly.
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Answer:

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Step-by-step explanation:

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3 years ago
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How much money is 15% of $14.90<br> SHOW YOUR WORK
Amiraneli [1.4K]

Answer:

The final price will be $12.67

Step-by-step explanation:

Discount = Original Price x Discount %/100

Discount = 14.9 × 15/100

Discount = 14.9 x 0.15

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Final Price = Original Price - Discount

Final Price = 14.9 - 2.235

Final Price = $12.67

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4 0
3 years ago
The substraction of a matrix B may be considered as the addition of the matrix (-1)B. Dose the commutative law of addition permi
GuDViN [60]

Answer:  The corrected statement is A - B = -B + A.

Step-by-step explanation:  Given that the subtraction of a matrix B may be considered as the addition of the matrix (-1)B.

We are given to check whether the commutative law of addition permit us to state that A - B = B - A.

If not, We are to correct the statement.

If the subtraction A - B is considered a the addition A + (-B), then the commutative law should be stated as follows :

A + (-B) = (-B) + A.

That is, A - B = -B + A.

Thus, the corrected statement is A - B = -B + A, not B - A.

6 0
3 years ago
How many liters each of a 35% acid solution and a 80% acid solution must be used to produce 60 liters of a 65% acid solution? (R
serg [7]

Solving a system of equations we will see that we need to use <u>40 liters of the 80% acid solution</u>, and the other <u>20 liters are of the 35% acid solution</u>.

<h3>How many liters of each solution do we need to use?</h3>

First, we need to define the variables:

  • x = liters of the 35% acid used.
  • y = liters of the 80% acid used.

We know that we want to produce 60 liters of 65% acid, then we have the system of equations:

x + y = 60

x*0.35 + y*0.80 = 60*0.65

(in the second equation we wrote the percentages in decimal form).

To solve this we need to isolate one of the variables in one equation and then replace it in other one, isolating x we get:

x = 60 - y

Replacing that in the other equation:

(60 - y)*0.35 + y*0.80 = 60*0.65

y*(0.80 - 0.35) = 60*(0.65 - 0.35)

y*0.45 = 60*0.30

y = 60*0.30/0.45 = 40

So we need to use <u>40 liters of the 80% acid solution</u>, and the other <u>20 liters are of the 35% acid solution</u>.

If you want to learn more about systems of equations:

brainly.com/question/13729904

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7 0
2 years ago
X + y = 4<br> 3x + 4y= 14
Vaselesa [24]
Y = 4 - x
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3 years ago
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