Given:
3x - y = 10
y = 4x-8
Required:
What is the value of x - y of the solution to the system?
Explanation:
3x - y = 10
y = 4x-8
substitute into one of the equations
[tex]\begin{gathered} 3x-(4x-8)=10 \\ \\ combine\text{ like terms} \\ \\ -x+8=10 \\ \\ -x=2 \\ \\ x=-2 \end{gathered}[/tex][tex]\begin{gathered} substitute\text{ value of x} \\ \\ 3\times(-2)-y=10 \\ \\ -6-y=10 \\ \\ -y=10+6 \\ \\ -y=16 \\ \\ y=-16 \end{gathered}[/tex][tex]\begin{gathered} substitute\text{ value into x-y:} \\ \\ -2-(-16) \\ \\ -2+16 \\ \\ 14 \end{gathered}[/tex]Required answer:
C. 14
