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3 years ago

Examine the system of equations. −3x + y = 9, 2x + 4y = 8 Which variable is most efficient to isolate?

Mathematics

2 answers:

Eduardwww [97]3 years ago

6 0

Good morning ☕️

Answer:

Step-by-step explanation:

It’s easier to isolate y in the first equation because the coefficient of y there is just 1.

the coefficient of x in the first equation is -3 and in the second equation is 2 then it’s not easy to isolate x in both equation.

solving the system:

−3x + y = 9

2x + 4y = 8

⇔

y = 3x + 9 (*)

2x + 4y = 8

now, we substitute y by 3x + 9 in equation 2:

2x + 4(3x + 9) = 8 ⇔ 14x + 36 = 8 ⇔ 14x = - 28 ⇔ x = -28/14 = -2

at this stage we substitute x by -2 in (*) to get y:

y = 3x + 9 ⇒ y = 3(-2) + 9 = -6 + 9 = 3

finally, the solution of the system is the ordered pair (-2 , 3).

_____________________________________________

iogann1982 [59]3 years ago

3 0

the y in the first equation

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Answer:

See Below

Step-by-step explanation:

The surface area of cylinder is given by the formula:

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Where

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<u>Halving diameter:</u>

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So, SA would be:

$SA=2\pi r^2 + 2\pi r h\\SA=2\pi (1)^2 + 2\pi (1) (9)\\SA=2\pi +18\pi\\SA=20\pi$

<u>Halving height:</u>

Height is 9, halving would make it 9/2 = 4.5

Now, calculating new SA:

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Original SA is $44\pi$ ,

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