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3 years ago

-5x+y=6 -3x+6y=-12 Solving systems of equations by substitution

1 answer:

4 0

if you isolate y in the top equation to get y=5x+6 then you can substiture y for 5x+6 in the bottom equation because thats what y equals

as of now you have -3x+6(5x+6)=-12 but if you use the distrubite property you would get -3x+30x+36=-12

then if you subtract 36 from both sides you would get -3x+30x=-48 then combine like terms to get 27x=-48 then divide both sides by 27 to get $x=\frac{-48}{27}$ or x≈1.8

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Solve this system by substitution. y = 3 y = -3x + 6 *Remember to write your answer as a coordinate point (x, y). I

DochEvi [55]

Answer:

(1, 3)

General Formulas and Concepts:

Pre-Algebra

Order of Operations: BPEMDAS

Brackets
Parenthesis
Exponents
Multiplication
Division
Addition
Subtraction

Left to Right

Equality Properties

Multiplication Property of Equality
Division Property of Equality
Addition Property of Equality
Subtraction Property of Equality

Algebra I

Coordinates (x, y)
Solving systems of equations using substitution/elimination

Step-by-step explanation:

Step 1: Define Systems

y = 3

y = -3x + 6

Step 2: Solve for x

Substitute in y: 3 = -3x + 6
[Subtraction Property of Equality] Subtract 6 on both sides: -3 = -3x
[Division Property of Equality] Divide -3 on both sides: 1 = x
Rewrite/Rearrange: x = 1

Step 3: Solve for y

Define original equation: y = -3(1) + 6
Multiply: y = -3 + 6
Add: y = 3

6 0

2 years ago

Write 12345678 times 10^-9 as a decimal.

labwork [276]

You answer would be 0.012345678.
Calculate it

5 0

3 years ago

Read 2 more answers

Please help!! second time posting !! algebra question, about functions!

kodGreya [7K]

Answer:

steps below

Step-by-step explanation:

y = (x-3) / x

replace x and y: x = (y-3) / y

y - 3 = xy

y - xy = 3

y(1 - x) = 3

y (f'(x)) = 3 / (1-x)

6 0

3 years ago

Initially 100 milligrams of a radioactive substance was present. After 6 hours the mass had decreased by 3%. If the rate of deca

Hitman42 [59]

Answer:

The half-life of the radioactive substance is 135.9 hours.

Step-by-step explanation:

The rate of decay is proportional to the amount of the substance present at time t

This means that the amount of the substance can be modeled by the following differential equation:

$\frac{dQ}{dt} = -rt$

Which has the following solution:

$Q(t) = Q(0)e^{-rt}$

In which Q(t) is the amount after t hours, Q(0) is the initial amount and r is the decay rate.

After 6 hours the mass had decreased by 3%.

This means that $Q(6) = (1-0.03)Q(0) = 0.97Q(0)$ . We use this to find r.

$Q(t) = Q(0)e^{-rt}$

$0.97Q(0) = Q(0)e^{-6r}$

$e^{-6r} = 0.97$

$\ln{e^{-6r}} = \ln{0.97}$

$-6r = \ln{0.97}$

$r = -\frac{\ln{0.97}}{6}$

$r = 0.0051$

$Q(t) = Q(0)e^{-0.0051t}$

Determine the half-life of the radioactive substance.

This is t for which Q(t) = 0.5Q(0). So

$Q(t) = Q(0)e^{-0.0051t}$

$0.5Q(0) = Q(0)e^{-0.0051t}$

$e^{-0.0051t} = 0.5$

$\ln{e^{-0.0051t}} = \ln{0.5}$

$-0.0051t = \ln{0.5}$

$t = -\frac{\ln{0.5}}{0.0051}$

$t = 135.9$

The half-life of the radioactive substance is 135.9 hours.

6 0

2 years ago

4(3x+2)−7x simplified

baherus [9]

Answer:

19x+8

Step-by-step explanation:

1) distribute the term outside the parenthesis to each term inside:

4*3x=12x

4*2=8

12x+8-7x

2) 12x+7x=19x

19x+8

Hope this helps!

7 0

3 years ago