Question

If you were to solve the system 2x+81=12 and 31−Sv=11 by substitution, what would be the best variable to solve for and from what equation?

A. x, in the second equation
B. y, in the second equation
C. x, in the first equation
D. y, in the first equation

Answer 1

To solve the given system of equations by substitution, we should solve for the variable x in the first equation, which is 2x + 81 = 12. By isolating x in this equation, we can substitute the value of x into the second equation to find the value of Sv.

Step-by-step explanation:

To solve the system 2x + 81 = 12 and 31 - Sv = 11 by substitution, we need to determine which variable to solve for and from which equation. In this case, the best variable to solve for is x, and we should solve for it in the first equation, which is 2x + 81 = 12. By isolating x in this equation, we can substitute the value of x into the second equation to find the value of Sv.

Step-by-step:

1. Start with the given system of equations: 2x + 81 = 12 and 31 - Sv = 11.
2. Solve the first equation for x: 2x + 81 = 12.
   Substract 81 from both sides: 2x = 12 - 81.
   Simplify: 2x = -69.
   Divide both sides by 2: x = -69/2 = -34.5.
3. Substitute the value of x into the second equation: 31 - Sv = 11.
   Replace x with -34.5: 31 - S(-34.5) = 11.
   Simplify: 31 + 34.5S = 11.
   Subtract 31 from both sides: 34.5S = 11 - 31.
   Simplify: 34.5S = -20.
   Divide both sides by 34.5: S = -20/34.5 = -0.58.