Math Problem Statement

Solve the equation 4x - 5y = -5 for x and y, find intercepts, and graph the line.

Solution

Let's go through each problem from the image step by step:

a. Solve: 4x5=54x - 5 = -5

To solve for xx, add 5 to both sides:

4x5+5=5+54x - 5 + 5 = -5 + 5

4x=04x = 0

Now, divide both sides by 4:

x=04=0x = \frac{0}{4} = 0

So, x=0x = 0.


b. Find the xx-intercept: 4x5y=54x - 5y = -5

The xx-intercept occurs when y=0y = 0. Substitute y=0y = 0 into the equation:

4x5(0)=54x - 5(0) = -5

4x=54x = -5

Now, divide both sides by 4:

x=54x = \frac{-5}{4}

So, the xx-intercept is x=54x = -\frac{5}{4} or 1.25-1.25.


c. Find yy when x=0x = 0: 4x5y=54x - 5y = -5

Substitute x=0x = 0 into the equation:

4(0)5y=54(0) - 5y = -5

5y=5-5y = -5

Now, divide both sides by 5-5:

y=1y = 1

So, y=1y = 1.


d. Solve for yy: 4x5y=54x - 5y = -5

To solve for yy, isolate yy on one side of the equation:

4x5y=54x - 5y = -5

Subtract 4x4x from both sides:

5y=4x5-5y = -4x - 5

Now, divide both sides by 5-5:

y=4x55y = \frac{-4x - 5}{-5}

Simplify:

y=45x+1y = \frac{4}{5}x + 1

So, y=45x+1y = \frac{4}{5}x + 1.


e. Graph: 4x5y=54x - 5y = -5

This is the equation of a straight line. To graph it, use the intercepts found earlier:

  • The xx-intercept is x=54x = -\frac{5}{4} or x=1.25x = -1.25,
  • The yy-intercept is y=1y = 1.

You can plot these two points on the graph:

  • (1.25,0)(-1.25, 0)
  • (0,1)(0, 1)

Then, draw a line through these two points.


Would you like any further details or help with another step? Here are some related questions:

  1. How do we check if a solution is correct for a linear equation?
  2. Can you explain how to calculate intercepts of more complex functions?
  3. What is the significance of the slope in the equation y=45x+1y = \frac{4}{5}x + 1?
  4. How would we solve this equation graphically using a different method?
  5. What would happen if the equation had a higher degree (like a quadratic)?

Tip: When graphing a line, the slope is crucial. In the equation y=45x+1y = \frac{4}{5}x + 1, the slope 45\frac{4}{5} tells us that for every 5 units we move horizontally (along the xx-axis), we move 4 units vertically (along the yy-axis).

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Math Problem Analysis

Mathematical Concepts

Linear Equations
Slope-Intercept Form
Algebra

Formulas

4x - 5y = -5
Slope-Intercept form y = mx + b

Theorems

Solving linear equations
Finding intercepts from equations

Suitable Grade Level

Grade 8-10