Find Intercepts from Slope-Intercept Form
Grade 7 students in Big Ideas Math Advanced 2 (Chapter 4: Graphing and Writing Linear Equations) learn to find x-intercepts and y-intercepts directly from slope-intercept form y = mx + b. The y-intercept is the constant b, and the x-intercept is found by setting y = 0 and solving for x.
Key Concepts
For a line in slope intercept form $y = mx + b$: • the $y$ intercept is $(0, b)$ it's given directly by the constant term • the $x$ intercept is found by setting $y = 0$ and solving: $0 = mx + b$, so $x = \frac{b}{m}$ (when $m \neq 0$).
Common Questions
How do you find intercepts from slope-intercept form?
In y = mx + b, the y-intercept is (0, b). To find the x-intercept, set y = 0 and solve: 0 = mx + b, giving x = -b/m.
What is the y-intercept in slope-intercept form?
The y-intercept is the constant term b in y = mx + b. It is the point (0, b) where the line crosses the y-axis.
How do you find the x-intercept from y = mx + b?
Substitute y = 0 and solve for x: 0 = mx + b, so x = -b/m. For example, for y = 2x + 3, x = -3/2.
What chapter in Big Ideas Math Advanced 2 covers intercepts?
Chapter 4: Graphing and Writing Linear Equations in Big Ideas Math Advanced 2 (Grade 7) covers finding intercepts.
What happens when a line passes through the origin in slope-intercept form?
When b = 0 (y = mx), both intercepts are at the origin (0, 0) because setting y = 0 gives x = 0.