Question

Difficulty: EasySystems of Linear Equations

A system of equations is shown below.

y=2(x5)y = -2(x - 5)
3x+y=133x + y = 13

What is the value of xx?

  1. A
    23
  2. B
    4
  3. 3Answer
  4. D
    8

Answer

The value of xx is 33.
Substituting the expression for yy from the first equation into the second equation gives 3x2(x5)=133x - 2(x - 5) = 13. Distributing the 2-2 yields 3x2x+10=133x - 2x + 10 = 13. Combining the xx terms gives x+10=13x + 10 = 13. Subtracting 10 from both sides of the equation yields x=3x = 3.

Step-by-Step Solution

1
Substitute the expression for yy from the first equation into the second equation.
3x2(x5)=133x - 2(x - 5) = 13
This substitution reduces the system to a single linear equation in terms of xx.
2
Apply the distributive property to simplify the equation.
3x2x+10=133x - 2x + 10 = 13
Multiplying 2-2 by xx gives 2x-2x, and multiplying 2-2 by 5-5 gives +10+10.
3
Combine like terms and isolate xx.
x+10=13x + 10 = 13, which simplifies to x=3x = 3
Subtracting 10 from both sides gives the value of xx.

Key Concept

Solving a system of linear equations using substitution.
Estimated Time:1m 0s
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