Question

Look at the line graphed below.

Which equation can be used to graph all the points on the line?

�
=
2
�
y=2x

�
=
�
+
1
y=x+1

�
=
�
−
1
y=x−1

�
=
2
�
−
1
y=2x−1

Answer 1

y = x + 1

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 ) = (1, 2) and (x₂, y₂ ) = (8, 9) ← 2 points on the line

m =
`(9-2)/(8-1)` =
`(7)/(7)` = 1

the line crosses the y- axis at (0, 1 ) ⇒ c = 1

y = x + 1 ← equation of line