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2 years ago

X+2y+z=5 2x-y+z=4 3x+y+4z=1

Mathematics

1 answer:

Bingel [31]2 years ago

8 0

X=1.5, y=2.5,z=-1.5 I used matrices to solve it.

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Hip hop music makes up 75% of Landon's music library. If he has downloaded 120 hip hop songs, how many songs does Landon have in

Otrada [13]

Answer: 160 songs.

Step-by-step explanation:

75% hip hop music - 120 songs

100% all music - x songs

Let's write the proportion:

$\dfrac{120}{75} =\dfrac{x}{100} \\\\75x=120 \cdot 100\\75x=12000\\75x : 75 = 12000 : 75\\x = 160$

Thus, Landon have 160 songs in his music library.

4 0

2 years ago

P(x) = x + 1x² – 34x + 343 d(x)= x + 9

Feliz [49]

Answer:

$x=\frac{9}{d-1},\:P=\frac{-297d+378}{\left(d-1\right)^2}+343$

Step-by-step explanation:

Let us start by isolating x for dx = x + 9.

dx - x = x + 9 - x > dx - x = 9.

Factor out the common term of x > x(d - 1) = 9.

Now divide both sides by d - 1 > $\frac{x\left(d-1\right)}{d-1}=\frac{9}{d-1};\quad \:d\ne \:1$ . Go ahead and simplify.

$x=\frac{9}{d-1};\quad \:d\ne \:1$ .

Now, $\mathrm{For\:}P=x+1x^2-34x+343, \mathrm{Subsititute\:}x=\frac{9}{d-1}$ .

$P=\frac{9}{d-1}+1\cdot \left(\frac{9}{d-1}\right)^2-34\cdot \frac{9}{d-1}+343$ .

Group the like terms... $1\cdot \left(\frac{9}{d-1}\right)^2+\frac{9}{d-1}-34\cdot \frac{9}{d-1}+343$ .

$\mathrm{Add\:similar\:elements:}\:\frac{9}{d-1}-34\cdot \frac{9}{d-1}=-33\cdot \frac{9}{d-1}$ > $1\cdot \left(\frac{9}{d-1}\right)^2-33\cdot \frac{9}{d-1}+343$ .

Now for $1\cdot \left(\frac{9}{d-1}\right)^2 > \mathrm{Apply\:exponent\:rule}: \left(\frac{a}{b}\right)^c=\frac{a^c}{b^c} > \frac{9^2}{\left(d-1\right)^2} = 1\cdot \frac{9^2}{\left(d-1\right)^2}$ .

$\mathrm{Multiply:}\:1\cdot \frac{9^2}{\left(d-1\right)^2}=\frac{9^2}{\left(d-1\right)^2}$ .

Now for $33\cdot \frac{9}{d-1} > \mathrm{Multiply\:fractions}: \:a\cdot \frac{b}{c}=\frac{a\:\cdot \:b}{c} > \frac{9\cdot \:33}{d-1} > \frac{297}{d-1}$ .

Thus we then get $\frac{9^2}{\left(d-1\right)^2}-\frac{297}{d-1}+343$ .

Now we want to combine fractions. $\frac{9^2}{\left(d-1\right)^2}-\frac{297}{d-1}$ .

$\mathrm{Compute\:an\:expression\:comprised\:of\:factors\:that\:appear\:either\:in\:}\left(d-1\right)^2\mathrm{\:or\:}d-1 > This\: is \:the\:LCM > \left(d-1\right)^2$

$\mathrm{For}\:\frac{297}{d-1}:\:\mathrm{multiply\:the\:denominator\:and\:numerator\:by\:}\:d-1 > \frac{297}{d-1}=\frac{297\left(d-1\right)}{\left(d-1\right)\left(d-1\right)}=\frac{297\left(d-1\right)}{\left(d-1\right)^2}$

$\frac{9^2}{\left(d-1\right)^2}-\frac{297\left(d-1\right)}{\left(d-1\right)^2} > \mathrm{Since\:the\:denominators\:are\:equal,\:combine\:the\:fractions}> \frac{a}{c}\pm \frac{b}{c}=\frac{a\pm \:b}{c}$

$\frac{9^2-297\left(d-1\right)}{\left(d-1\right)^2} > 9^2=81 > \frac{81-297\left(d-1\right)}{\left(d-1\right)^2}$ .

Expand $81-297\left(d-1\right) > -297\left(d-1\right) > \mathrm{Apply\:the\:distributive\:law}: \:a\left(b-c\right)=ab-ac$ .

$-297d-\left(-297\right)\cdot \:1 > \mathrm{Apply\:minus-plus\:rules} > -\left(-a\right)=a > -297d+297\cdot \:1$ .

$\mathrm{Multiply\:the\:numbers:}\:297\cdot \:1=297 > -297d+297 > 81-297d+297 > \mathrm{Add\:the\:numbers:}\:81+297=378 > -297d+378 > \frac{-297d+378}{\left(d-1\right)^2}$

Therefore $P=\frac{-297d+378}{\left(d-1\right)^2}+343$ .

Hope this helps!

5 0

3 years ago

Simplify the expression -2(2x+y)-7x+2y

wolverine [178]

Answer:

Step-by-step explanation:

6 0

2 years ago

HELP ME ASAP! Will give BRAINLIEST! Please read the question THEN answer correctly! No guessing. Check ALL that apply.

Elena L [17]

Answer:

x = -2 or x = 1/3 thus: B & C

Step-by-step explanation:

Solve for x over the real numbers:

2 x^2 + 7 x - 2 = 2 x - x^2

Subtract 2 x - x^2 from both sides:

3 x^2 + 5 x - 2 = 0

The left hand side factors into a product with two terms:

(x + 2) (3 x - 1) = 0

Split into two equations:

x + 2 = 0 or 3 x - 1 = 0

Subtract 2 from both sides:

x = -2 or 3 x - 1 = 0

Add 1 to both sides:

x = -2 or 3 x = 1

Divide both sides by 3:

Answer: x = -2 or x = 1/3

3 0

2 years ago

The cost of new carpet, c, varies directly with the area of the room being carpeted, a. Carpet for a 150-square foot dining room

11111nata11111 [884]

Answer:

3. C=4a

Step-by-step explanation:

600/150 = 4 (one square foot = $4)

5 0

2 years ago