Question

Write an equation that passes through (-2, - 11) and is perpendicular to x + 4y=8​

Answer 1

y = 4x - 3

Explanation:

Firstly rearrange into the form y = mx + c;

⇒
`y = -(1)/(4)x + 2`

Secondly, find the gradient of the line using the formula for perpendicular lines;

⇒
`m_(1)m_(2) = -1`

⇒
`-(1)/(4)m_(2) = -1`

⇒
`m_(2) = 4`

Now substitute into the formula for a straight line;

⇒
`y - y_(1) = m(x - x_(1))`

⇒
`y + 11 = 4(x + 2)`

⇒
`y = 4x - 3`