Math Question x5

Question

Find an equation for the line perpendicular to y=−1/6x+2 with x-intercept at 

x = -8.Write your answer in the form y=mx+b.

Answer 1

Hi Bon, so they are giving you an equation in slope-intercept form and asking you to find the line that is perpendicular but goes through the given point, in this case the x-intercept.

Here's a little how to guide:

1. Find perpendicular slope by taking the negative reciprocal of the given slope (take the opposite sign and flip the fraction).
2. the given slope is -1/6 so the negative reciprocal would be +6/1 (or just 6)
3. Use the perpendicular slope you found and the given point to plug into y=mx+b and solve for b so you can get your new equation. given point: (-8, 0)

The given point does not always have to be the x-intercept, it could be any point the line goes through (remember the x-intercept is the x-value when y = 0 since it's on the x-axis)

y = mx + b

0 = 6(-8) + b

0 = -48 + b

+48 +48

48 = b

3. Now use the perpendicular slope for "m" and the value for "b" you found to form your new equation:

y = 6x + 48

Answer 2

Slope of perpendicular line will -1/slope.

so m=6, use intercept (-8, 0)

0 = 6*(-8) + b

b = 48,

y = 6x + 48