Math  /  Algebra

QuestionFor the relation: y=2x4y=2 x-4, sketch the graph of the relation and its inverse, then write the equation for the inverse.
Clear All Draw: \square
Inverse: y=y= \square

Studdy Solution

STEP 1

What is this asking? We're taking a line, drawing it, then flipping it over the diagonal line y=xy=x to get its inverse, and then writing the equation of that flipped line! Watch out! Don't flip-flop the *x* and *y* without also solving for the new *y*!

STEP 2

1. Graph the original relation
2. Find the inverse relation
3. Graph the inverse relation

STEP 3

Alright, let's **graph** this bad boy!
Our equation is y=2x4y = 2x - 4.
This is in **slope-intercept form**, which is y=mx+by = mx + b, where *m* is the **slope** and *b* is the **y-intercept**.

STEP 4

Here, our **slope** is m=2m = \mathbf{2} and our **y-intercept** is b=4b = \mathbf{-4}.
The y-intercept tells us that the line crosses the y-axis at the point (0,4)(0, -4).
Plot that point!

STEP 5

The **slope** is 22, which we can write as 21\frac{\mathbf{2}}{\mathbf{1}}.
Remember, slope is **rise over run**.
So, from our **y-intercept** (0,4)(0, -4), we go **up 2** and **over 1** to the **right**.
This gives us another point on the line: (1,2)(1, -2).
Plot that point!
Now draw a straight line through the two points.
Boom! We've graphed our original line.

STEP 6

To find the inverse, we **swap** *x* and *y* in the original equation.
So, y=2x4y = 2x - 4 becomes x=2y4x = 2y - 4.

STEP 7

Now, we need to **solve for** *y*.
First, let's **add 4** to both sides of the equation: x+4=2y4+4x + 4 = 2y - 4 + 4, which simplifies to x+4=2yx + 4 = 2y.

STEP 8

Next, we **divide both sides** by 22 to isolate *y*: x+42=2y2\frac{x + 4}{2} = \frac{2y}{2}.
This simplifies to y=x+42y = \frac{x + 4}{2}, or y=12x+2y = \frac{1}{2}x + 2.
This is the equation of our inverse relation!

STEP 9

Now, let's **graph** the inverse.
Our equation is y=12x+2y = \frac{1}{2}x + 2.
This is also in **slope-intercept form**, where our **slope** is m=12m = \frac{\mathbf{1}}{\mathbf{2}} and our **y-intercept** is b=2b = \mathbf{2}.

STEP 10

The **y-intercept** tells us the line crosses the y-axis at (0,2)(0, 2).
Plot that point!

STEP 11

Our **slope** is 12\frac{1}{2}, so from the **y-intercept**, we go **up 1** and **over 2** to the **right**.
This gives us the point (2,3)(2, 3).
Plot that point!
Draw a straight line through these two points, and there you have it – the graph of the inverse!

STEP 12

The graph of y=2x4y = 2x - 4 is a line passing through (0,4)(0, -4) and (1,2)(1, -2).
The inverse relation is y=12x+2y = \frac{1}{2}x + 2, and its graph is a line passing through (0,2)(0, 2) and (2,3)(2, 3).

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