Question

What is the slope of the line perpendicular to y = -4x + 7?A) -4B) 4C) 1/4D) -1/4

Answer 1

Two lines are perpendicular when the product between the slopes of the lines is equal to -1, then, if we have the following lines:

$\begin{gathered} y_1=m_1x+b_1 \\ y_2=m_2x+b_2 \end{gathered}$

they will be perpendicular if,

$m_1\cdot m_2=-1$

According to the exercise, the first line is:

$y=-4x+7$

the slope for this line is -4.

Write the equation that makes two lines perpendicular,

$-4\cdot m_2=-1$

solve for m2,

$\begin{gathered} m_2=\frac{-1}{-4} \\ m_2=\frac{1}{4} \end{gathered}$

Answer:

The slope of the line perpendicular to y=-4x+7 is 1/4.