Question

Line A has a gradient of -4. Line B is perpendicular to line A.

a) What are the coordinates of the y-intercept of line B?

b) What is the equation of line B? Give your answer in the form y = mx + c, where m and c are integers or fractions written in their simplest form.​

Answer 1

We are here given that the slope of line A is -4 and line B is perpendicular to line A . As we know that the product of slopes of two perpendicular lines is -1 . Therefore ,

`\longrightarrow m_Am_B =-1\\`

`\longrightarrow m_B =-(1)/(-4)=\boxed{(1)/(4)}`

From the given graph we can see that the line B intersects y axis at (0,6) . Therefore this is the coordinate of the y intercept of line B .

Now we can use the slope intercept form of the line to find the equation of line B,

`\longrightarrow y = m_Bx + c \\`

`\longrightarrow \underline{\underline{y =(1)/(4)x +6}}`

And we are done!