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2 years ago

Who can solve these three ??

Mathematics

2 answers:

icang [17]2 years ago

5 0

Answer:

1) x = 9

2) y = 16

3) y = -1

Step-by-step explanation:

Do PEMDAS in reverse.

For every equation, your goal is to seperate the variable (x,y, or whatever letter) by itself.

1) 2x-7 = 11

Add 7 to both sides.

2x = 18

Divide both sides by 2.

x = 9

2) $\frac{3}{4}y = 12$

Divide both sides by 3/4 (which turns into multiplying by 4/3).

Left side

$\frac{3}{4}x * \frac{4}{3}\\\\\frac{3}{4}x * \frac{4}{3} = \frac{3*4}{4*3}x\\1x\\x$

Right side

$12*\frac{4}{3}\\\\\frac{12}{1} *\frac{4}{3}\\\\ \frac{12}{1} *\frac{4}{3} = \frac{12*4}{1*3}\\\\\frac{48}{3} \\16$

3) 9(y+3) = 18

Remember do PEMDAS in reverse.

Divide both sides by 9.

y+3 = 2

Subtract both sides by 3.

y = -1

Sladkaya [172]2 years ago

4 0

1. X = 9
2. Y=16
3. Y= -1

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11Alexandr11 [23.1K]

Answer:

Question 1: $dm/dt=0.2m$

Question 2: $m=Ae^{(0.2t)}$

Question 3: $m=10e^{(0.2t)}$

Question 4: $m=10g$

Explanation:

Question 1: Write down the differential equation the mass of the bacteria, m, satisfies: m′= .2m

a) By definition: $m'=dm/dt$

b) Given: $rate=0.2m$

c) By substitution: $dm/dt=0.2m$

Question 2: Find the general solution of this equation. Use A as a constant of integration.

a) Separate variables

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$\int dm/m=\int 0.2dt$

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c) Antilogarithm

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Question 3. Which particular solution matches the additional information?

Use the measured rate of 4 grams per hour after 3 hours

$t=3hours,dm/dt=4g/h$

First, find the mass at t = 3 hours

$dm/dt=0.2m\\\\4=0.2m\\\\m=4/0.2\\\\m=20g$

Now substitute in the general solution of the differential equation, to find A:

$m=Ae^{(0.2t)}\\\\20=Ae^{(0.2\times 3)}\\\\A=20/e^{(0.6)}\\\\A=10.976$

Round A to 1 significant figure:

A = 10.

Particular solution:

$m=10e^{(0.2t)}$

Question 4. What was the mass of the bacteria at time =0?

Substitute t = 0 in the equation of the particular solution:

$m=10e^{0}\\\\m=10g$

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a2 – b2 = (a + b)(a – b) or (a – b)(a + b).
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In order to use the 'Difference of Squares' formula to factor a binomial, the binomial must contain two perfect squares that are separated by a subtraction symbol.

x^2 - 4 fits this, because x^2 and 4 are both perfect squares, and they are separated by a subtraction symbol.
All you do here to factor, is take the square root of each term.

√x^2 = x
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Now that we have our square roots, x and 2, we substitute these numbers into the form (a + b)(a - b).

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Our answer is final (x + 2)(x - 2), which can also be written as (x - 2)(x + 2), it doesn't make a difference which order you put it in.

Anyway, Hope this helps!!
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