Question

Write the equation of the line that is perpendicular to x+y=-5 and passes through the point (7,3)

Answer 1

Answer:

x - y = 4

Step-by-step explanation:

The equation of a line in slope- intercept form is

y = mx + c ( m is the slope and c the y- intercept )

Given

x + y = - 5 ( subtract x from both sides )

y = - x - 5 ← in slope- intercept form

with slope m = - 1

Given a line with slope m then the slope of a line perpendicular to it is

$m_{perpendicular}$ = - $\frac{1}{m}$ = - $\frac{1}{-1}$ = 1 , thus

y = x + c ← is the partial equation

To find c substitute (7, 3) into the partial equation

3 = 7 + c ⇒ c = 3 - 7 = - 4

y = x - 4 ← equation in slope- intercept form

subtract y from both sides

0 = x - y - 4 ( add 4 to both sides )

4 = x - y , that is

x - y = 4 ← equation in standard form