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3 years ago

Please help!

1 answer:

8 0

2/3x = -5/2y + 2
2/3x + 5/2y = 2 (when one unknown goes over to the other side, it changes its sign - 5/2y was negative, but when it went to the left, it became positive)
now, you can multiply both sides by 6 (because it is GCF for denominators 3 and 2) to get rid of fractions
6*2/3x + 6*5/2y = 6*2
4x + 15y = 12

So the correct answer is A. 4x + 15y = 12

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A carpenter bought a piece of wood that was 112 centimeters long. Then he sawed 24.53 centimeters off the end. How long is the p

saul85 [17]

Answer:

87.47 cm

Step-by-step explanation:

112-24.53 is 87.47

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3 years ago

Match each vector operation with its resultant vector expressed as a linear combination of the unit vectors i and j.

Cloud [144]

Answer:

3u - 2v + w = 69i + 19j.

8u - 6v = 184i + 60j.

7v - 4w = -128i + 62j.

u - 5w = -9i + 37j.

Step-by-step explanation:

Note that there are multiple ways to denote a vector. For example, vector u can be written either in bold typeface "u" or with an arrow above it $\vec{u}$ . This explanation uses both representations.

$\displaystyle \vec{u} = \langle 11, 12\rangle =\left(\begin{array}{c}11 \\12\end{array}\right)$ .

$\displaystyle \vec{v} = \langle -16, 6\rangle= \left(\begin{array}{c}-16 \\6\end{array}\right)$ .

$\displaystyle \vec{w} = \langle 4, -5\rangle=\left(\begin{array}{c}4 \\-5\end{array}\right)$ .

There are two components in each of the three vectors. For example, in vector u, the first component is 11 and the second is 12. When multiplying a vector with a constant, multiply each component by the constant. For example,

$3\;\vec{v} = 3\;\left(\begin{array}{c}11 \\12\end{array}\right) = \left(\begin{array}{c}3\times 11 \\3 \times 12\end{array}\right) = \left(\begin{array}{c}33 \\36\end{array}\right)$ .

So is the case when the constant is negative:

$-2\;\vec{v} = (-2)\; \left(\begin{array}{c}-16 \\6\end{array}\right) =\left(\begin{array}{c}(-2) \times (-16) \\(-2)\times(-6)\end{array}\right) = \left(\begin{array}{c}32 \\12\end{array}\right)$ .

When adding two vectors, add the corresponding components (this phrase comes from Wolfram Mathworld) of each vector. In other words, add the number on the same row to each other. For example, when adding 3u to (-2)v,

$3\;\vec{u} + (-2)\;\vec{v} = \left(\begin{array}{c}33 \\36\end{array}\right) + \left(\begin{array}{c}32 \\12\end{array}\right) = \left(\begin{array}{c}33 + 32 \\36+12\end{array}\right) = \left(\begin{array}{c}65\\48\end{array}\right)$ .

Apply the two rules for the four vector operations.

$\displaystyle \begin{aligned}3\;\vec{u} - 2\;\vec{v} + \vec{w} &= 3\;\left(\begin{array}{c}11 \\12\end{array}\right) + (-2)\;\left(\begin{array}{c}-16 \\6\end{array}\right) + \left(\begin{array}{c}4 \\-5\end{array}\right)\\&= \left(\begin{array}{c}3\times 11 + (-2)\times (-16) + 4\\ 3\times 12 + (-2)\times 6 + (-5) \end{array}\right)\\&=\left(\begin{array}{c}69\\19\end{array}\right) = \langle 69, 19\rangle\end{aligned}$

Rewrite this vector as a linear combination of two unit vectors. The first component 69 will be the coefficient in front of the first unit vector, i. The second component 19 will be the coefficient in front of the second unit vector, j.

$\displaystyle \left(\begin{array}{c}69\\19\end{array}\right) = \langle 69, 19\rangle = 69\;\vec{i} + 19\;\vec{j}$ .

$\displaystyle \begin{aligned}8\;\vec{u} - 6\;\vec{v} &= 8\;\left(\begin{array}{c}11\\12\end{array}\right) + (-6) \;\left(\begin{array}{c}-16\\6\end{array}\right)\\&=\left(\begin{array}{c}88+96\\96 - 36\end{array}\right)\\&= \left(\begin{array}{c}184\\60\end{array}\right)= \langle 184, 60\rangle\\&=184\;\vec{i} + 60\;\vec{j} \end{aligned}$ .

$\displaystyle \begin{aligned}7\;\vec{v} - 4\;\vec{w} &= 7\;\left(\begin{array}{c}-16\\6\end{array}\right) + (-4) \;\left(\begin{array}{c}4\\-5\end{array}\right)\\&=\left(\begin{array}{c}-112 - 16\\42+20\end{array}\right)\\&= \left(\begin{array}{c}-128\\62\end{array}\right)= \langle -128, 62\rangle\\&=-128\;\vec{i} + 62\;\vec{j} \end{aligned}$ .

$\displaystyle \begin{aligned}\;\vec{u} - 5\;\vec{w} &= \left(\begin{array}{c}11\\12\end{array}\right) + (-5) \;\left(\begin{array}{c}4\\-5\end{array}\right)\\&=\left(\begin{array}{c}11-20\\12+25\end{array}\right)\\&= \left(\begin{array}{c}-9\\37\end{array}\right)= \langle -9, 37\rangle\\&=-9\;\vec{i} + 37\;\vec{j} \end{aligned}$ .

7 0

3 years ago

What is the value of these coins?

Alborosie

Answer:

$2.39

Step-by-step explanation:

4 pennies=4

2 nickels=10

10 dimes=100

5 quarters=125

$2.39

3 0

3 years ago

Read 2 more answers

Mandi learned that each 10% of charge on her cell phone gave her an hour and twenty minutes of use. While playing a game today o

Sonja [21]

Answer:

3hrs 12 mins

Step-by-step explanation:

For every 10% charge she gets 1hr 20mins (or 80 mins)

Charge drop = (81% - 57%) = 24%

Since 10% gives 80 mins;

24% gives (24/10) x 80 mins = 192 mins

since 1hr = 60 mins

192 mins = 192/60 = 3hrs 12 mins

3 0

4 years ago

How to solve 2x^2 - 4x = 3

zhenek [66]

Answer:

1 ± i(1/2)√2

Step-by-step explanation:

Write this quadratic in standard form: subtract 3 from both sides. This results in 2x^2 - 4x - 3 = 0. Let's apply the quadratic formula. The coefficients of the x terms are 2, -4 and -3, so the discriminant is (-4)^2 - 4(2)(-3), or 16 - 24 = -8.

Following the format of the quadratic formula, we get

-(-4) ±i2√8 4 ±i2√2

x = ----------------- = --------------- = 1 ± i(1/2)√2

4 4

6 0

3 years ago