The correct sentence is: "f now looks like this, is a line with a slope equal to 0.5."
We use "is" instead of "equals" to describe a quality or characteristic of something, such as the slope of a line. In this case, we're describing the slope of the line, which is a characteristic of f, so we use "is" to indicate that the slope is 0.5.
Additionally, "slope equal to" is the correct way to phrase the slope of the line. We use "equal to" to indicate that the slope has a specific value, in this case 0.5.