Question

In the piece-wise function graphed below, which is the correct equation for when

-2 ≤ x ≤ 0

Answer 1

y = 3x + 5

Explanation:

In the interval - 2 ≤ x ≤ 0 the graph is a straight line.

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 = (y₂ - y₁ ) / (x₂ - x₁ )

with (x₁, y₁ ) = (- 2, - 1) and (x₂, y₂ ) = (0, 5) ← 2 points on the line

m =
`(5+1)/(0+2)` =
`(6)/(2)` = 3

The line intercepts the y- axis at (0, 5) ⇒ c = 5

y = 3x + 5 ← equation for - 2 ≤ x ≤ 0