Question

What is the equation of this line in slope-intercept form?

A) y = - 1/3 x - 1
B) 3x - 1
C) y = 3x + 1
D) y = -3x - 1

Answer 1

Explanation:

It is D.

The general form for line is " y=ax+b"

which a is slope.

We have 2 known points : (-1,2) and (1,-4)

We can find slope by writing this :

slope =
`(y_(2) - y_(1) )/(x_(2) - x_(1)) = (-4-2)/(1-(-1))=(-6)/(2) = -3\\`

⇒ y=-3x+b

in order to find b, let's try one of the given points :

if x=1 then y=-4 :

y=(-3×1)+b=-4 ⇒ -3+b=-4⇒ b=-4+3=-1⇒ b=-1

so let's complete the line equation :

y=-3x-1

Answer 2

Answer:A

Explanation:

The equation of a line in slope-intercept form is y = mx + b, where m is the slope of the line and b is the y-intercept (the point where the line crosses the y-axis).

Out of the given options, only option A is in the slope-intercept form, with a slope of -1/3 and a y-intercept of -1. Therefore, the equation of the line in slope-intercept form is:

y = -1/3 x - 1

So the answer is A.