For the function y = 1/4x + 3, find the x-value that makes y = -1.

Question

I need to find the x-value of this function.

Answer 1

y = 1/4x +3

y =-1

-1 = 1/4x + 3

Subtract both sides by -3

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

-4 = 1/4x

Multiply both sides by 4

-16 = x

So, x = -16

Answer 2

Let's plug in y = -1 into this equation

-1 = 1/4x + 3

Now, we need to solve the equation for x. To do so, we want x to be by itself on one side of the equation. We will use inverse operations to get the x by itself. First, subtract 3 from either side to under the +3 on the right side of the equation.

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

-4 = 1/4x

Next, we will divide by 1/4 to undo the *1/4. Dividing by 1/4 is the same as multiplying by 4, so we will multiply each side by 4.

-4 * 4 = 1/4x * 4

-16 = x

And that's our final answer! When x = -16, y = -1.