Question

Write the equation of the line that passed through the point (-1,-4) that is perpendicular to the line

Answer 1

Answer:

The line that meets these conditions is y = 1.5x - 2.5

If you want to use fractions, it would be y = 3x/2 - 5/2

Step-by-step explanation:

To get a line perpendicular to y = -(2/3)x + 1, We can start by finding its slope.  That's easy enough as a perpendicular slope is the negative reciprocal of the given one.  As this has a slope of -2/3, our new slope has to be 3/2, or 1.5

All we need to do then is express that rate of change relative to the given point (-1, -4).  We can do this by expanding the classic equation:

Δy = sΔx

We can write that as such:

y - (-4) = 1.5(x - (-1))

y + 4 = 1.5(x + 1)

y + 4 = 1.5x + 1.5

y  = 1.5x + 1.5 - 4

y = 1.5x - 2.5

Or if you want to express those numbers as fractions, it would be y = 3x/2 - 5/2.

To make sure the answer's correct, we can simply plug -1 in as the x value, and see if we get y = -4:

y = 3(-1) / 2 - 5/2

y = -3 / 2 - 5 / 2

y = -8 / 2

y = -4

So we know that our answer is correct (assuming that the slope is correct, which it is - a perpendicular line always has the negative reciprocal of the other line's slope).