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2 years ago

Pre-Algebra Due urgently Tysm

Mathematics

2 answers:

Vesna [10]2 years ago

7 0

Answer:

1. x = 5 2. y = 4 3. x = -2

Step-by-step explanation:

2x - y = 9 -5x + 2y = 13 3x + 4y = -6

4x + y = 21 5x + y = -1 7x(-1) + 4y(-1) = -14(-1) <(multiply all by -1)

6x = 30 3y = 12 -4x = 8

6 6 3 3 4 4

x = 5 y = 4 x = -2

statuscvo [17]2 years ago

6 0

I don’t know the answer I just need points

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What must be true of PQ?

yulyashka [42]

Interesting question
Usually when you look at something like that construction, you think that AB has been bisected by PQ and that the two segments are perpendicular. They are perpendicular but nowhere is that stated. So the answer is C because all the other answers are wrong.

PQ is congruent AB is not correct. As long as the arcs are equal and meet above and below AB there is no proof of congruency. In your mind widen the compass legs so that they are wider than AB and redraw the arcs. You get a larger PQ, but it has all the original properties of PQ except size.

PQ is not congruent to AQ. How would you prove conguency? You'd have to put both lines into triangles that can be proved congruent. It can't be done.

The two lines are not parallel. They are perpendicular. That can be proven. They meet at right angles to each other (also provable).

8 0

2 years ago

A pharmacist has an 18% alcohol solution and a 40% alcohol solution. How much of each should he mix together to make 10 liters o

ladessa [460]

X = amount of the 18% solution

y = amount of the 40% solution

we know the 18% solution has only 18% of alcohol, the rest is maybe water or something, now, how many liters is 18%? well, 18% of anything is just (18/100) * anything, so, 18% of x is just (18/100) *x or 0.18x, and that's how many liters are there.

likewise, how many liters are there in the 40% solution? well, (40/100) * y, or 0.4y, that many.

we know the mixture has to yield 10 liters at 20% alcohol, how many liters of only alcohol is that? well, (20/100) * 10, or 2 liters.

$\bf \begin{array}{lccclll}
&\stackrel{liters}{amount}&\stackrel{alcohol~\%}{quantity}&\stackrel{liters}{alcohol}\\
&------&------&------\\
\textit{18\% solution}&x&0.18&0.18x\\
\textit{40\% solution}&y&0.40&0.4y\\
------&------&------&------\\
mixture&10&0.20&2
\end{array}$

$\bf \begin{cases}
x+y=10\implies \boxed{y}=10-x\\
0.18x+0.4y=2\\
----------\\
0.18x+0.4\left( \boxed{10-x} \right)=2
\end{cases}
\\\\\\
0.18x-0.4x+4=2\implies -0.22x=-2
\\\\\\
x=\cfrac{-2}{-0.22}\implies x=\cfrac{100}{11}\implies x=9\frac{1}{11}$

how much of the 40% solution? well y = 10 - x

3 0

3 years ago

Two trains leave two different stations 300 km apart; the first starts at noon and the second at 12 15 h. Travelling on parallel

alexgriva [62]

Answer:

See below

Step-by-step explanation:

From noon to 1500 is three hours

train A then travels 3x where x = speed in km/hr

train B only travels for 2.45 hours and covers

2.45 ( x + 15) where x + 15 is its speed in km/hr

these two values sum to the 300 km distance

3x + 2.45 ( x + 15) = 300

3x + 2.45 x + 36.75 = 300

x = 48.3 km/hr x+15= 63.3 km / hr

8 0

2 years ago

The boys' basketball team at Washington High School has been doing really well so far this year. In the past six games, they've

o-na [289]

The answer is 75.3 but the three is forever

7 0

3 years ago

Read 2 more answers

A number plus itself, plus twice itself, plus 4 times itself is equal to -104

NARA [144]

The scenario will will be represented by: $x+x+2x+4x=-104$

The number will be -13

Step-by-step explanation:

We have to convert the given situation into the mathematical form

Let x be the number

Then

"a number plus itself"

x+x

"plus twice itself"

x+x+2x

"plus 4 times itself"

x+x+2x+4x

"is equal to -104"

$x+x+2x+4x=-104$

This can also be written as:

$x+x+2x+4x=-104\\8x=-104\\Dividing\ both\ sides\ by\ 8\\\frac{8x}{8}=\frac{-104}{8}\\x=-13$

Keywords: Linear Equation

Learn more about linear equation at:

#LearnwithBrainly

7 0

3 years ago