Question

Which of these lines are perpendicular to y - 2x +3.OA. x+2y=8OB-x+2y = 8OC. 2x+y=8OD. 2x=y=8

Answer 1

The given equation is

`y=-2x+3`

Remember that perpendicular lines must meet the following rule

`m_1\cdot m_2=-1`

Where the product is between the two slopes. In this case, we have

`m_1=-2`

We use the formula above

`\begin{gathered} -2\cdot m_2=-1 \\ m_2=(-1)/(-2)=(1)/(2) \end{gathered}`

This means the perpendicular line must have a coefficient of 1/2.

The right answer is B, because

`\begin{gathered} -x+2y=8 \\ 2y=8+x \\ y=(8+x)/(2) \\ y=4+(x)/(2) \end{gathered}`

Where the slope is 1/2 as we should get.