Question

What is the equation of the line that passes through the point (4, 3) and is perpendicular to the line x + y = 4?

Answer 1

ANSWER

$y - x = - 1$

EXPLANATION

The required equation passes through:

(4,3) and is perpendicular to x+y=4.

Rewrite the given equation in slope-intercept form:

$y = - x + 4$

The slope of this line is -1.

The slope of the required line is perpendicular to this line, so we find the negative reciprocal of this slope.

$m= - \frac{1}{ - 1} = 1$

The equation of the line can be found using:

$y - y_1 = m(x - x_1)$

We substitute the slope and point to obtain:

$y - 3 = 1(x - 4)$

We simplify to get:

$y - 3 = x - 4$

$y - x = - 4 + 3$

The required equation is

$y - x = - 1$