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3 years ago

Solve this system by substitution, 50 points!

Mathematics

1 answer:

antiseptic1488 [7]3 years ago

7 0

Answer:

Solve:

-X - Y - Z =-8

- 4X +4Y +5Z=7

2X + 2Z =4 is the same as x + z = 2. Thus, z = 2 - x.

Subst. 2 - x for z in the 1st and second equations.

-X - Y - Z =-8 becomes -x - y - (2 -x) = -8

- 4X +4Y +5Z=7 becomes -4x + 4y + 5(2-x) = 7

Now we have 2 equations in only 2 unknowns. Let's simplify them!

-x - y - 2 + x = -8 which becomes -y = -6, or y = 6

-4x + 4y + 10 - 5x = 7 which becomes -9x + 4y = 7 - 10 = -3

Now substitute 6 for y in this last equation: -9x + 4(6) = -3, or

-9x + 24 = -3, or

-9x = - 27 => x = 3

Then x = 3, y = 6 and z = 2 - x, or z = 2-3, or z = -1.

The solution is (3, 6, -1). Check it!!

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Chase goes out to lunch. The bill, before tax and tip, was $11.90. A sales tax of 9% was added on. Chase tipped 17% on the amoun

WINSTONCH [101]

Answer:

$15.17

Step-by-step explanation:

First we calculate the value for the sales tax:

$11.90 \times \frac{9}{100 } = 1.07$

we then add the value for the sales tax ($1.07) to the initial bill:

$11.90 + 1.07 = 12.97$

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after we will add the value for the tip to the value that we have for the bill ( this is the new value that includes the sales tax) to find the total cost:

$12.97+ 2.20 = 15.17$

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3 years ago

What sets of numbers does 3 over 5 belongs

stiks02 [169]

Step-by-step explanation:

integers are whole numbers.

3/5 is a rational number because it represents a ratio of two integers (and denominator ≠0).

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4 years ago

Find the value of x.

lawyer [7]

Answer:

$\huge\boxed{x=\sqrt{70}}$

Step-by-step explanation:

ΔABC and ΔADB are similar (AAA).

Therefore the corresponging sides are in proportion:

$\dfrac{AB}{AD}=\dfrac{AC}{AB}$

Substitute:

$AB=x\\AC=7+3=10\\AD=7$

$\dfrac{x}{7}=\dfrac{10}{x}$ cross multiply

$(x)(x)=(7)(10)\\\\x^2=70\to x=\sqrt{70}$

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4 years ago

What is the solution to the system of equations graphed below???

german

Answer:

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Step-by-step explanation:

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3 years ago

Can anyone solve the last question?

sesenic [268]

As stated in (i), the equation of the line is: ln y = -0.015x + .26
(By the way, I checked your answers for parts (i) and (ii) and they are both correct)

(iii)
Plug in (1.1) for y and solve:
ln (1.1) = -0.015x + .26
0.095 = -0.015x + .26
-0.165 = - 0.015x
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Answer: x = 10.979

7 0

3 years ago