Math Problem Statement

A line passes through the point (-4, -8) and has a slope of 5/4. Write an equation in slope-intercept form for this line.

Solution

We are given:

  • A point (4,8)(-4, -8).
  • A slope of 54\frac{5}{4}.

We need to find the equation of the line in slope-intercept form, which is y=mx+by = mx + b, where mm is the slope and bb is the y-intercept.

Step-by-Step Solution:

  1. Use the point-slope form of the line equation: The point-slope form is given by: yy1=m(xx1)y - y_1 = m(x - x_1) where (x1,y1)(x_1, y_1) is the point on the line and mm is the slope.

  2. Plug in the given values:

    • Slope m=54m = \frac{5}{4},
    • Point (x1,y1)=(4,8)(x_1, y_1) = (-4, -8).

    So, the point-slope equation becomes: y(8)=54(x(4))y - (-8) = \frac{5}{4}(x - (-4)) which simplifies to: y+8=54(x+4)y + 8 = \frac{5}{4}(x + 4)

  3. Expand and solve for yy: y+8=54x+544y + 8 = \frac{5}{4}x + \frac{5}{4} \cdot 4 y+8=54x+5y + 8 = \frac{5}{4}x + 5

  4. Isolate yy: y=54x+58y = \frac{5}{4}x + 5 - 8 y=54x3y = \frac{5}{4}x - 3

Final Answer:

The equation of the line in slope-intercept form is: y=54x3y = \frac{5}{4}x - 3

Would you like further details on how each step was completed or have any questions? Here are five related questions to explore:

  1. How do you find the equation of a line if given two points instead of a point and a slope?
  2. What is the significance of the slope and y-intercept in the equation of a line?
  3. Can you convert a line equation from standard form to slope-intercept form?
  4. What does a slope of 54\frac{5}{4} indicate about the steepness of the line?
  5. How would the equation change if the slope was negative instead?

Tip: When dealing with equations of lines, always double-check your arithmetic and signs to avoid common mistakes.

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Math Problem Analysis

Mathematical Concepts

Algebra
Linear Equations
Slope-Intercept Form

Formulas

y = mx + b
Point-slope form: y - y1 = m(x - x1)

Theorems

Slope-Intercept Formula

Suitable Grade Level

Grades 8-10