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4 years ago

Solve the expression 3x(n+7)+2n-13

Mathematics

1 answer:

Oxana [17]4 years ago

5 0

You cant solve, only simplify so the answer is 3nx+21x+2n-13.

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Does anyone know how to do these? I don’t want the answers I need someone to explain how to do them so I can solve it. Thanks

ElenaW [278]

Hi! This type of equation is actully really simple to solve once you learn how so I'll only do a few and let you solve the rest.

To solve 3x + 6 = 18 you just need to remember that whatever action you do on one side of the equal sign you have to do on the other as well, and you just need to get the variable isolated on one side and the constant on the other.

So subtract 6 from both of the constants (6 and 18) to get to 3x = 12.

Then divide both sides by 3 to isolate x and you get x = 4.

To solve x/7 -9 = -7 you have to add 9 to both sides to get x/7 = 2. Then because it's a fraction with a denominator of 7 you multiply both sides by 7 to get x = 14.

To solve 8x - 2x = -36 you combine like terms to get 6x = -36 then divide both sides by 6 to get x = -6.

Hope this is what you were looking for and explained in an understandable way, if not I apologize. :)

5 0

3 years ago

How many solutions exist for the given equation? 3(x+10)+6=3(x+12)

Helen [10]

3x+30+6=3x+36

⇒3x+36=3x+36

⇒3x−3x=36−36

⇒0⋅x=0
infinite solutions of x for all x∈R

6 0

3 years ago

Read 2 more answers

GIVING OUT BRAINLIEST TO WHOEVER GETS ALL OF THEM RIGHT

Thepotemich [5.8K]

Answer:

4) $\frac{x}{7\cdot x +x^{2}}$ is equivalent to $\frac{1}{7+x}$ for all $x \ne -7$ . (Answer: A)

5) $\frac{-14\cdot x^{3}}{x^{3}-5\cdot x^{4}}$ is equivalent to $-\frac{14}{1-5\cdot x}$ for all $x \ne \frac{1}{5}$ . (Answer: B)

6) $\frac{x+7}{x^{2}+4\cdot x - 21}$ is equivalent to $\frac{1}{x-3}$ for all $x \ne 3$ . (Answer: None)

7) $\frac{x^{2}+3\cdot x -4}{x+4}$ is equivalent to $x - 1$ . (Answer: None)

8) $\frac{2}{3\cdot a}\cdot \frac{2}{a^{2}}$ is equivalent to $\frac{4}{3\cdot a^{3}}$ for all $a\ne 0$ . (Answer: A)

Step-by-step explanation:

We proceed to simplify each expression below:

4) $\frac{x}{7\cdot x +x^{2}}$

(i) $\frac{x}{7\cdot x +x^{2}}$ Given

(ii) $\frac{x}{x\cdot (7+x)}$ Distributive property

(iii) $\frac{1}{7+x} \cdot \frac{x}{x}$ Distributive property

(iv) $\frac{1}{7+x}$ Existence of multiplicative inverse/Modulative property/Result

Rational functions are undefined when denominator equals 0. That is:

$7+x = 0$

$x = -7$

Hence, we conclude that $\frac{x}{7\cdot x +x^{2}}$ is equivalent to $\frac{1}{7+x}$ for all $x \ne -7$ . (Answer: A)

5) $\frac{-14\cdot x^{3}}{x^{3}-5\cdot x^{4}}$

(i) $\frac{-14\cdot x^{3}}{x^{3}-5\cdot x^{4}}$ Given

(ii) $\frac{x^{3}\cdot (-14)}{x^{3}\cdot (1-5\cdot x)}$ Distributive property

(iii) $\frac{x^{3}}{x^{3}} \cdot \left(-\frac{14}{1-5\cdot x} \right)$ Distributive property

(iv) $-\frac{14}{1-5\cdot x}$ Commutative property/Existence of multiplicative inverse/Modulative property/Result

Rational functions are undefined when denominator equals 0. That is:

$1-5\cdot x = 0$

$5\cdot x = 1$

$x = \frac{1}{5}$

Hence, we conclude that $\frac{-14\cdot x^{3}}{x^{3}-5\cdot x^{4}}$ is equivalent to $-\frac{14}{1-5\cdot x}$ for all $x \ne \frac{1}{5}$ . (Answer: B)

6) $\frac{x+7}{x^{2}+4\cdot x - 21}$

(i) $\frac{x+7}{x^{2}+4\cdot x - 21}$ Given

(ii) $\frac{x+7}{(x+7)\cdot (x-3)}$ $x^{2} -(r_{1}+r_{2})\cdot x +r_{1}\cdot r_{2} = (x-r_{1})\cdot (x-r_{2})$

(iii) $\frac{1}{x-3}\cdot \frac{x+7}{x+7}$ Commutative and distributive properties.

(iv) $\frac{1}{x-3}$ Existence of multiplicative inverse/Modulative property/Result

Rational functions are undefined when denominator equals 0. That is:

$x-3 = 0$

$x = 3$

Hence, we conclude that $\frac{x+7}{x^{2}+4\cdot x - 21}$ is equivalent to $\frac{1}{x-3}$ for all $x \ne 3$ . (Answer: None)

7) $\frac{x^{2}+3\cdot x -4}{x+4}$

(i) $\frac{x^{2}+3\cdot x -4}{x+4}$ Given

(ii) $\frac{(x+4)\cdot (x-1)}{x+4}$ $x^{2} -(r_{1}+r_{2})\cdot x +r_{1}\cdot r_{2} = (x-r_{1})\cdot (x-r_{2})$

(iii) $(x-1)\cdot \left(\frac{x+4}{x+4} \right)$ Commutative and distributive properties.

(iv) $x - 1$ Existence of additive inverse/Modulative property/Result

Polynomic function are defined for all value of $x$ .

$\frac{x^{2}+3\cdot x -4}{x+4}$ is equivalent to $x - 1$ . (Answer: None)

8) $\frac{2}{3\cdot a}\cdot \frac{2}{a^{2}}$

(i) $\frac{2}{3\cdot a}\cdot \frac{2}{a^{2}}$

(ii) $\frac{4}{3\cdot a^{3}}$ $\frac{a}{b}\cdot \frac{c}{d} = \frac{a\cdot b}{c\cdot d}$ /Result

Rational functions are undefined when denominator equals 0. That is:

$3\cdot a^{3} = 0$

$a = 0$

Hence, $\frac{2}{3\cdot a}\cdot \frac{2}{a^{2}}$ is equivalent to $\frac{4}{3\cdot a^{3}}$ for all $a\ne 0$ . (Answer: A)

6 0

3 years ago

An animal shelter has 32 puppies. If the puppies are 32% of the total dog and cat population, how many dogs and cats are in the

vova2212 [387]

32 puppies and 67 cats

4 0

4 years ago

Read 2 more answers

4. A local DVD rental machine rents

Mrrafil [7]

It takes 16 movie rentals for both options to be the same price

Solution:

Given that, A local DVD rental machine rents movies out to customers for $5.75 per movie.

A digital movie company allows you to rent movies for $3.25 but requires a membership fee of $40.

We have to find how many movie rentals will it take for both options to be the same price?

Now, let the number of movies rented be "n"

Then, according to the given information,

$\begin{array}{l}{5.75 \times n=3.25 \times n+40} \\\\ {5.75 n=3.25 n+40} \\\\ {5.75 n-3.25 n=40} \\\\ {2.50 n=40} \\\\ {n=\frac{40}{2.5}=16}\end{array}$

Hence, it takes 16 movies to be the same price for both options.

3 0

4 years ago