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eduard
3 years ago
14

Need pre-cal help. Will mark best answer brainliest

Mathematics
1 answer:
OlgaM077 [116]3 years ago
5 0

so, let's keep in mind that

\bf \begin{array}{|c|ll} \cline{1-1} \textit{a\% of b}\\ \cline{1-1} \\ \left( \cfrac{a}{100} \right)\cdot b \\\\ \cline{1-1} \end{array}

so let's make a quick table of those solutions, say A, B, C solutions with x,y,z liters of acid, with an acidity of 0.25, 0.40 and 0.60 respectively.


\bf \begin{array}{lcccl} &\stackrel{solution}{quantity}&\stackrel{\textit{\% of }}{amount}&\stackrel{\textit{liters of }}{amount}\\ \cline{2-4}&\\ A&x&0.25&0.25x\\ B&y&0.40&0.4y\\ C&z&0.60&0.6z\\ \cline{2-4}&\\ mixture&78&0.45&35.1 \end{array} \\\\\\ \begin{cases} x+y+z=78\\ 0.25x+0.4y+0.6z=35.1 \end{cases}


we know she's using "z" liters and those are 3 times as much as "y" liters, so z = 3y.


\bf \begin{cases} x+y+3y=78\\ x+4y=78\\[-0.5em] \hrulefill\\ 0.25x+0.4y+0.6(3y)=35.1\\ 0.25x+0.4y=1.8y=35.1\\ 0.25x+2.2y=35.1 \end{cases}\implies \begin{cases} x+4y=78\\\\ 0.25x+2.2y=35.1 \end{cases} \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ x+4y=78\implies \boxed{x}=78-4y \\\\\\ \stackrel{\textit{using substitution on the 2nd equation}}{0.25\left( \boxed{78-4y} \right)+2.2y=35.1}\implies 19.5-y+2.2y=35.1


\bf 1.2y=15.6\implies y=\cfrac{15.6}{1.2}\implies \blacktriangleright y=13 \blacktriangleleft \\\\\\ x=78-4y\implies x=78-4(13)\implies \blacktriangleright x=26 \blacktriangleleft \\\\\\ z=3y\implies z=3(13)\implies \blacktriangleright z=39 \blacktriangleleft \\\\[-0.35em] \rule{34em}{0.25pt}\\\\ ~\hfill \stackrel{25\%}{26}\qquad \stackrel{40\%}{13}\qquad \stackrel{60\%}{39}~\hfill

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ahrayia [7]

Answer:

first question: c. x = 1

6. B. y = -2x - 8

Step-by-step explanation:

first question:

perpendicular means that when it intersects, it makes a right angle.

the equation y = 5 would be parallel to any of the answers with y = ___ because all of those would result in horizontal lines

either of the x = ___ would be perpendicular to y = 5

since it has to pass through the point (1,3) that means that the equation must be x = 1

the equation x = 1 passes through any point beginning with (1 , _)

6.

parallel means that the equations have the same slope. therefore, we can eliminate both A and C

using the given point (-2 , -4),we can plug into the y = mx + b format to solve

m = -2   x = -2   y = -4

-4 = (-2)(-2) + b --> -4 = 4 + b --> b = -8

finally, our equation comes out to be y = -2x - 8

4 0
3 years ago
a varies directly as b and inversely as the square of c. If a = 197 when b = 5 and c = 5, find a if b = 3 and c = 3
SSSSS [86.1K]
With the information you provided, we can find an equation.

A=kB/(C^2)             (k is a constant)

197= 5k/(5^2)   
197=5k/25
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So find a if b=3 and c=3

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3 years ago
Given the situation, which inequality models the number of additional weeks marie needs to continue saving to afford the home re
Artemon [7]

In the inequality models, the number of additional weeks is 1558+60x≥2158.

Given that the initial savings is $1558, the amount needed is $2158 and additional savings is $60 weekly.

Let the number of weeks be x.

So, she will save 60x in x weeks.

Total savings after x weeks is

Initial saving +60x       .......(1)

According to the question, she needs $1258 for repair.

So, that means the minimum requirement is 2158.

≥2158      ........(2)

Combine equations (1) and (2) and get

Initial savings +60x≥2158

As given that the initial savings is 1558.

Substitute this in above inequality and get

1558+60x≥2158

To find the number of weeks find value of x.

Subtract 1558 from either sides of the inequality.

1558+60x-1558≥2158-1558

60x≥600

Divide both sides with 60 as

60x÷60≥600÷60

x≥10

Hence, the inequality that models the number of additional weeks marie needs to continue saving to afford the home repairs is 1558+60x≥2158 and she needs to save $60 for at least 10 weeks.

Learn about inequality from here brainly.com/question/9774970

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2 years ago
Sum of the arithmetic sequence-Find each sum- 2 + 5 + 8 + ... +41
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301

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1 year ago
Read 2 more answers
What is the solution for <br> x+y&gt;2<br> 2x-y&gt;1
blagie [28]

Answer:

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3 years ago
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