Finding the Slope from an Equation
3. Rearranging Equations to Reveal the Slope
Alright, so what happens if you're not just handed the slope on a silver platter? Sometimes, you'll need to do a little detective work to uncover it. Often, the line will be presented to you as an equation, and the slope will be hiding within. The most common form to encounter is the standard form: Ax + By = C. While it's a perfectly respectable equation format, it doesn't exactly scream, "Hey, I'm the slope!"
That's where the slope-intercept form comes to the rescue: y = mx + b. Remember that little 'm'? That's your slope! So, your mission, should you choose to accept it, is to transform the equation from standard form (or any other form) into slope-intercept form. This involves isolating 'y' on one side of the equation.
Let's say you have the equation 2x + y = 5. To get it into slope-intercept form, you need to get 'y' by itself. Subtract 2x from both sides, and you get y = -2x + 5. Aha! The slope is -2. That means any line parallel to this one also has a slope of -2.
Now, you might encounter slightly more complex equations with coefficients in front of the 'y'. For instance, 3x + 2y = 6. First, subtract 3x from both sides: 2y = -3x + 6. Then, divide everything by 2: y = (-3/2)x + 3. The slope is -3/2. See? A little bit of algebra, and the slope is revealed! Don't let those numbers intimidate you; just follow the steps, and you'll crack the code every time.