how do you write a linear equation when f(-1)=5 and f(3)=4

Answer 1

We can use the point-slope formula y - y₁ = m(x - x₁).

First let's find our m which is the slope. m = (y₂ - y₁)/(x₂ - x₁) = (5-4)/(-1-3) = -1/4

Now the formula is y - y₁ = -1/4(x - x₁).

Substitute in values for y₁ and x₁. I'll be using f(3) = 4, where x₁ = 3 and y₁ = 4.

y - 4 = -1/4(x - 3)

Now solve for y.

y - 4 = -1/4x + 3/4

y = -1/4x + 19/4

Answer 2

Start with two-point form:

(y - 5) / (x + 1) = (5 - 4) / (3 + 1)

Can you continue and answer?