Question

4. Write an equation of the line that passes through the points (-1, 3) and (2, -3).

A. y = -2x + 1
B. y = -2x + 5
C. y = (-½)x + (5/2)
D. y = (-½)x + (½)

Answer 1

Find the slope
slope formula is
(y₂ - y₁) = m(x₂ - x₁)
plug the given coordinates
y₂ = -3 y₁ = 3
x₂ = 2 x₁ = -1
(-3 - 3) = m(2 -(-1))
-6 = m(3)
Divide by 3

`(-6)/(3) = (3m)/(3)`
3 and 3 cancels out
-2 = m

Now, we know the slope, the equation of a line is:
y = mx + c
So plug in any of the given coordinates with its slope to find c
-3 = (-2)(2) + c
-3 = -4 + c
add 4 to either sides
-3 = -4 + c
+4 +4
1 = c
so the equation of this line is
y = -2x + 1
Answer is A. y = -2x + 1