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Gennadij [26K]
3 years ago
12

How do you know what number to multiply everything by using the elimination method on systems of equations??

Mathematics
1 answer:
Marrrta [24]3 years ago
8 0

Answer:

See below  

Step-by-step explanation:

You multiply the equations by numbers that will give you the least common multiple of the coefficients.

Suppose you have a system of two equations:

\begin{cases}(1)& 2x + y = 40\\(2) & x + 2.5y = 60\end{cases}\\

You can choose to eliminate either x or y.

1. Eliminating x

The coefficients of x are 2 and 1. The least common multiple is 2, so you multiply (1) by 1 and (2) by 2 to get

\begin{array}{lrcll}(3) & 2x + y & = & 40 &\ \\(4) & 2x + 5y & = & 120 & }\\\end{array}

Then you can subtract (3) from (4) and get

4y = 80. Solve for y.

2. Eliminating y

The coefficients of y are 1 and 2.5. The least common multiple is 2.5, so you multiply (1) by 2.5 and (2) by 1 to get

\begin{array}{lrcll}(5) & 5x + 2.5y & = & 100 &\ \\(6) & x + 2.5y & = & 60 & }\\\end{array}

Then you can subtract (6) from (5) and get

4x = 40. Solve for x.

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Find the product of the given complex number and its conjugate.<br> 1/5+4i
nasty-shy [4]

Answer:

-15.96

Step-by-step explanation:

A conjugate is a binomial with the sign inside changed. So the conjugate of (1/5 + 4i) is (1/5 - 4i)

Set the original and the conjugate next to each other and F.O.I.L. Multiply the first numbers of each binomial, the 1/5 and the 1/5 to get 1/25. This is the "F."

Multiply the outer members, the 1/5 and the 4i to get - 60i. This is the "O."

Multiply the inner  numbers  ( the + 4i and the 1/5) to get + 60i. This is the "I."

Multiply the positive 4i and the negative 4i to get 16i squared

The positive 60i and the negative 60i cancel each other out.

The i squared changes into - 1. This makes the 16 negative.

Add 1/25 to - 16 to get - 15.96

4 0
3 years ago
Solve for x. Round to the nearest tenth, if necessary.
DENIUS [597]

Answer:

x=3.5 cm

Step-by-step explanation:

90/2 = 45 degrees

Soh Cah Toa

We have opposite and hypotenuse making sin.

Length×Sin(Angle)

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Rounded the the nearest tenth makes 3.5cm

6 0
3 years ago
In the figure above, circles A and B are tangent to each other and to the large circle. If the radius of circle A
Ne4ueva [31]

Answer:

The answer to your question is A = 200.96 u²

Step-by-step explanation:

Data

Radius A = 6

Radius B = 2

π = 3.14

Area = ?

Formula

Area = πr²

Process

1.- Calculate the radius of the large circle

Radius = radius of circle A + radius of circle B

Radius = 6 + 2

Radius = 8

2.- Substitute in the formula

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Area = 200.96 u²

6 0
3 years ago
I need help on this with this problem
IgorLugansk [536]

Answer:

<h2>P = 40.56 ft</h2>

Step-by-step explanation:

We have three sides of a rectangle, and a semicircle.

Three sides of a rectangle: 10ft + 8ft + 10ft = 28ft.

The circumference of a whole circle: C = π(8) = 8π ft.

The semicircle: 8π : 2 = 4π ft

Using π ≈ 3.14 → 4π ≈ (4)(3.14) = 12.56 ft

The perimeter of the figure: P = 28ft + 12.56ft = 40.56ft

6 0
3 years ago
What is sin, tan, and sec
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Answer:

Those are functions on a calculator.  Mostly used for Trigonometry.

Step-by-step explanation:

4 0
3 years ago
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