Question

10. A system of equations is shown below.3x - y = 10y = 4x-8What is the value of x - y of the solution to the system?C. 14A -98D. 62B-18

Answer 1

Given:

3x - y = 10

y = 4x-8

Required:

What is the value of x - y of the solution to the system?

Step-by-step explanation:

3x - y = 10

y = 4x-8

substitute into one of the equations

`\begin{gathered} 3x-(4x-8)=10 \\ \\ combine\text{ like terms} \\ \\ -x+8=10 \\ \\ -x=2 \\ \\ x=-2 \end{gathered}`
`\begin{gathered} substitute\text{ value of x} \\ \\ 3*(-2)-y=10 \\ \\ -6-y=10 \\ \\ -y=10+6 \\ \\ -y=16 \\ \\ y=-16 \end{gathered}`
`\begin{gathered} substitute\text{ value into x-y:} \\ \\ -2-(-16) \\ \\ -2+16 \\ \\ 14 \end{gathered}`

Required answer:

C. 14