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3 years ago

Solve the system of linear equations by adding or subtracting.

Mathematics

1 answer:

Sav [38]3 years ago

7 0

Answer:

add bc when you subtract it will mess up your answer bc were literally doing the same thing in school at least i think adding right

Step-by-step explanation:

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Using Cramer's rule to solve linear systems.

Rzqust [24]

Answer: Last Option

$x=2,\ y=-5$

Step-by-step explanation:

Cramer's rule says that given a system of equations of two variables x and y then:

$x =\frac{Det(A_X)}{Det(A)}$

$y =\frac{Det(A_Y)}{Det(A)}$

For this problem we know that:

$Det(A) = |A|=\left|\begin{array}{ccc}4&-6\\8&-2\\\end{array}\right|$

Solving we have:

$|A|= 4*(-2) -(-6)*8\\\\|A|=40$

$Det(A_X) = |A_X|=\left|\begin{array}{ccc}38&-6\\26&-2\\\end{array}\right|$

Solving we have:

$|A_X|=38*(-2) - (-6)*26\\\\|A_X|=80$

$Det(A_Y) = |A_Y|=\left|\begin{array}{ccc}4&38\\8&26\\\end{array}\right|$

Solving we have:

$|A_Y|=4*(26) - (38)*8\\\\|A_Y|=-200$

Finally

$x =\frac{|A_X|}{|A|} = \frac{80}{40}\\\\x=2$

$y =\frac{|A_Y|}{|A|} = \frac{-200}{40}\\\\y=-5$

4 0

3 years ago

The Drawing of a building, shown below, has a scale of 1 inch to 30 feet. What is the Actual height, in feet, of a building?

tatyana61 [14]

Well what were given:
1 inch = 30 feet

The drawing of the building of this problem has the height of 1.25 inches and base of 0.75 inches.

Actual height:
1.25 inches * 30 feet/inch = 37.50 feet

Actual base:
0.75 inches * 30 feet/inch = 22.50 feet

So in this problem the answer would be "A" 22.50 Aka 22.5 For the building. Hope this helps you! (:

7 0

3 years ago

Twice the difference of a number and 9 equals 5.

emmasim [6.3K]

Answer:

Step-by-step explanation:

if the number is x then you know 2x-9=5

2x=14

x=7

so the number is 7

8 0

3 years ago

What percent is shaded in the grid? Answer:

Keith_Richards [23]

I can’t see a picture of the grid

4 0

3 years ago

Determine which of the following expressions requires combining like terms before it is considered to be in its simplest form. S

polet [3.4K]

4x + 3y - 7xa2 + a2 - b

3 0

3 years ago

Read 2 more answers