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klemol [59]
3 years ago
13

2x-4y=8 and 7x-3y=61 solve by substitution

Mathematics
2 answers:
mrs_skeptik [129]3 years ago
8 0
2x= 8+4y. (Add 4y and move it to the other side)

X=8+4y/2 so X= 4+2y. (Divide both sides by 2)

Sub in 4+2y for x so 7(4+2y)-3y=61

Distribute: 28+ 14y -3y=61
Subtract 28 and add the y’s. 11y=33
Y=3
Ratling [72]3 years ago
4 0

Answer:

(10, 3)

Step-by-step explanation:

Solve by Substitution

2x − 4y = 8 and 7x − 3y = 61

Solve for x in the first equation.

x = 4 + 2y 7x − 3y = 61

Replace all occurrences of x with 4 + 2y in each e quation.

Replace all occurrences of x in 7x − 3y = 61 with 4 + 2y. 7 (4 + 2y) − 3y = 61

x = 4 + 2y

Simplify 7 (4 + 2y) − 3y.

28 + 11y = 61

x = 4 + 2y

Solve for y in the first equation.

Move all terms not containing y to the right side of the equation.

11y = 33

x = 4 + 2y

 Divide each term by 11 and simplify.

y = 3

x = 4 + 2y

 

Replace all occurrences of y with 3 in each equation.

Replace all occurrences of y in x = 4 + 2y with 3. x = 4 + 2 (3)

y = 3

Simplify 4 + 2 (3).

x = 10

y = 3

The solution to the system is the complete set of ordered pairs that are valid solutions.

(10, 3)

The result can be shown in multiple forms.

Point Form:

(10, 3)

Equation Form:

x = 10, y = 3

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Reika [66]

Answer:

After 43 minutes, the bacteria will be 40 remainings.

Step-by-step explanation:

Given that:

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After time (t) = 18 mins

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Using the model:

A = A_o e^{k*t}

240=800 e^{k*18}

\dfrac{240}{800}= e^{18k}

0.3= e^{18k}

By applying natural log on both sides, we get:

In(0,3) = 18k (In e)

- 1.20397 = 18 k * (1)

18 k = -1.20397

k =  -1.20397/ 18

k = - 0.06688

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After time (t), the bacteria population (A) = 40

Now;

40 = 800 e^{k*t}

\dfrac{40 }{800}= e^{-0.07*t}

0.05= e^{-0.07*t}

In (0.05) = -0.07t * In (e)

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givi [52]

Answer:

The graph of the function opens downwards.

Step-by-step explanation:

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3 years ago
Find three consecutive positive integers such that the product of the first and​ third, minus the​ second, is 1 more than 7 time
Bas_tet [7]
--------------------------------------------------------------------
Define x :
--------------------------------------------------------------------
Let the smallest number be x.
First number = x
Second Number = x + 1
Third Number = x + 2

--------------------------------------------------------------------
Construct equation :
--------------------------------------------------------------------
x(x+2) - (x+1) = 7(x+2) + 1

--------------------------------------------------------------------
Solve x :
--------------------------------------------------------------------
x(x + 2) - (x + 1) = 7(x + 2) + 1
x² + 2x - x - 1 = 7x + 14 + 1
x²- 6x - 16 = 0
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Since x is a positive integer, it cannot be negative.
⇒x = 8

--------------------------------------------------------------------------
Answer: The three numbers are 8, 9 and 10.
--------------------------------------------------------------------------
6 0
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