What is y-2=-3 (x-7) in standard form A.y-2=--3x+21
B.y=-3x+23
C.3x+y-23=0
D.3x+y=23

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  D.  3x +y = 23

Step-by-step explanation:

If you know what "standard form" is, then you recognize that only one offered answer choice is actually in standard form. That is the correct choice.

  3x + y = 23

Standard form for a linear equation is ...

  ax +by = c

where a, b, c are mutually prime integers and a ≥ 0. If a = 0, then b > 0. (The leading coefficient is positive.)

n = sqrt(7) - 5 or n = -5 - sqrt(7)

Step-by-step explanation:

Solve for n:

(n^2 + 10 n + 18)/(n + 5) = 0

Multiply both sides by n + 5:

n^2 + 10 n + 18 = 0

Subtract 18 from both sides:

n^2 + 10 n = -18

Add 25 to both sides:

n^2 + 10 n + 25 = 7

Write the left hand side as a square:

(n + 5)^2 = 7

Take the square root of both sides:

n + 5 = sqrt(7) or n + 5 = -sqrt(7)

Subtract 5 from both sides:

n = sqrt(7) - 5 or n + 5 = -sqrt(7)

Subtract 5 from both sides:

 n = sqrt(7) - 5 or n = -5 - sqrt(7)