The Solving for the y-intercept exercise used to appear under the Algebra I Math Mission. This exercise finds the y-intercepts on linear graphs.
Types of Problems
There are two types of problems in this exercise:
- Find the y-intercept of the equation: This problem provides a linear equation written in standard form. The student is asked to find the y-intercept of the equation and provide the answer in an ordered pair slot.
- Find the b in the formula: This problem provides an equation in slope-intercept form (with b unknown) and a point. The student will use the point to find the y-intercept of the line.
Solving linear equations and substituting values for variables are needed to perform this exercise in the standard way. Graphing could be used to avoid these skills.
- The y-intercept is found by replacing x with zero and solving.
- Since the Find the y-intercept of the equation problem is practically the same, dividing the isolated number on the right by the coefficient to the y will always provide the single number that needs to be inserted.
- On the Find the b in the formula problem, If the point is and the equation is , the answer will be .
Calculator Programs for TI83/84 series
For the Find the b in the formula problem:
- Prompt X,Y,M
- Disp Y-MX>Frac
- Problems like this occur on SATs and other standardized tests.
- Linear models are common in business and the sciences and the y-intercept often provides information about the model such as initial values.