To express in terms of , isolate : get it alone on one side of the equation. Graph the given line in Desmos for a quick check, then undo the -term and divide by the number multiplying . Watch the sign of the -term when you move it.
Hints
- Hint 1
The y-intercept is where the line crosses the vertical axis, so there. Graph the given equation and read that point. What value must your finished expression give when ?
- Hint 2
To isolate means to get alone. The equation has beside , so use the opposite operation: add to both sides.
- Hint 3
The coefficient of is the number multiplying it. Once you have alone, divide both sides by . Keep the entire expression on the other side together.
Step-by-step
Graph to check, then isolate
Step 1Get a sign check from the graph
Type in Desmos and click where the line crosses the vertical axis. Desmos shows , and the line rises as increases. So your answer must give when and must rise with . That crossing is called the y-intercept.
- Step 2
Move the -term away from
An inverse operation undoes an operation. Add to both sides to cancel :
The -term is now positive, matching the line's rise.
- Step 3
Get alone
Divide both sides by , the number multiplying :
This gives when and expresses in terms of . Choice D.