Question

What is the y intercept
x y
34 -52
51 -65
68 -78

Answer 1

y- intercept = - 26

Explanation:

to find the y- intercept, obtain the equation of the line in slope- intercept form

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 ) = (34, - 52) and (x₂, y₂ ) = (68, - 78) ← 2 ordered pairs from the table

m =
`(-78-(-52))/(68-34)` =
`(-78+52)/(34)` =
`(-26)/(34)` = -
`(13)/(17)` , then

y = -
`(13)/(17)` x + c

to find c substitute any of the ordered pairs into the equation and solve for c

using (51, - 65 ) , then

- 65 = -
`(13)/(17)` (51) + c = - 39 + c ( add 39 to both sides )

- 26 = c

then y- intercept = - 26