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3 years ago

How to solve x-4y=11 and 5x-7y=-10 using elimination

1 answer:

OverLord2011 [107]3 years ago

6 0

$x-4y=11\ /\cdot(-5)\\5x-7y=-10 \\\\-5x+20y=-55\\5x-7y=-10\\--------\\-5x+20y+5x-7y=-55-10\\13y=-65\ /:13\\y=-5\\\\$

$x-4y=11\ /\cdot7\\5x-7y=-10\ /\cdot(-4) \\\\7x-28y=77\\-20x+28y=40\\---------\\7x-28y-20x+28y=77+40\\-13x=117\ /:(-13)\\x=-9\\\\Ans.\ \ x=-9\ \ and\ \ y=-5$

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If a 12 volt battery produces a current of 36 amperes what is the resistance

bekas [8.4K]

Answer:

1/3

Step-by-step explanation:

resistance=voltage/current

resistance =12/36

resistance= 1/3

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3 years ago

A pendulum swings through an angle of 20 degrees each second. If the pendulum is 40 inches long how far does the tip move each s

Olin [163]

If the pendulum is 40 inches long, its tip moves 13.96” each second. I am hoping that this answer has satisfied your query and it will be able to help you in your endeavor, and if you would like, feel free to ask another question.

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3 years ago

Find the value of x please

valkas [14]

Answer:

Step-by-step explanation:

because if you minus 155 and 80 then add 10 because its a trianagle s so you have to use the polymerson method so you get 85

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3 years ago

4 A curve has equation y=x^3 - 2x² +5. Find the coordinates of its two stationary points.

vodomira [7]

Answer:

Stationary points are (0, 5) and (4/3, 103/27)

Step-by-step explanation:

At stationary point (turning point), dy/dx :

$y = {x}^{3} - 2 {x}^{2} + 5 \\ \frac{dy}{dx} = 3 {x}^{2} - 4x \\ \\ \frac{dy}{dx} = x(3x - 4)$

but dy/dx = 0:

$x(3x - 4) = 0 \\ either \: x \: is \: 0 \: and \: (3x - 4) = 0 \\ x = 0 \\ and \\ 3x - 4 = 0 \\ x = \frac{4}{3}$

let y = x³ - 2x² + 5:

$when \: x \: is \: 0 \\ y = 5 \\ when \: x \: is \: \frac{4}{3} \\ \\ y = {( \frac{4}{3}) }^{3} - 2 {( \frac{4}{3} )}^{2} + 5 \\ \\ y = \frac{103}{27}$

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3 years ago

What fraction does point S represent?

slavikrds [6]

Answer:

Step-by-step explanation:

So what you gotta do is count the lines. You don't count the one with one on it, but you count all the way through to 2. That gets you eight, so each line is 1/8. 1-2 in 1/8 intervals. 1 1/4 multiply 2 on the numerator and denominator gets 1 2/8, 1 1/2 multiply 4 on the numerator and denominator gets you 1 4/8. Counting the lines, each of those matches up. The first interval is 1 1/8.

7 0

3 years ago