Question

19. Which of the following equations represents a line that

passes through the points (-2, 4) and (-7, 9)?

Answer 1

y = - x + 2

Explanation:

the equation of a line in slope- intercept form is

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

calculate m using the slope formula

m =
`(y_(2)-y_(1) )/(x_(2)-x_(1) )`

with (x₁, y₁ ) = (- 2, 4 ) and (x₂, y₂ ) = (- 7, 9 )

m =
`(9-4)/(-7-(-2))` =
`(5)/(-7+2)` =
`(5)/(-5)` = - 1 , then

y = - x + c ← partial equation

to find c substitute either of the 2 points into the partial equation

using (- 2, 4 )

4 = 2 + c ⇒ c = 4 - 2 = 2

y = - x + 2 ← equation of line