Questions: You plant two flowers in a garden. The equations y=12.2x+16 and y=8.9x+16 model the heights y of the flowers, in millimeters, after x days. What does the y-intercept of each equation represent? Will the flowers ever be the same height?
What does the y-intercept of each equation represent?
- The rate of growth of the flower
- The height of the flower after 10 days
- The height of the flower when planted
- The difference of the flowers' heights
Transcript text: You plant two flowers in a garden. The equations $y=12.2 x+16$ and $y=8.9 x+16$ model the heights $y$ of the flowers, in millimeters, after $x$ days. What does the $y$-intercept of each equation represent? Will the flowers ever be the same height?
What does the $y$-intercept of each equation represent?
The rate of growth of the flower
The height of the flower after 10 days
The height of the flower when planted
The difference of the flowers' heights
Solution
Solution Steps
Step 1: Identify the \( y \)-intercept in each equation
The \( y \)-intercept of a linear equation \( y = mx + b \) is the value of \( y \) when \( x = 0 \). For the given equations:
\( y = 12.2x + 16 \) has a \( y \)-intercept of \( 16 \).
\( y = 8.9x + 16 \) has a \( y \)-intercept of \( 16 \).
Step 2: Interpret the meaning of the \( y \)-intercept
The \( y \)-intercept represents the height of the flowers when \( x = 0 \), which corresponds to the time when the flowers are planted. Therefore, the \( y \)-intercept represents:
The height of the flower when planted.
Step 3: Determine if the flowers will ever be the same height
To determine if the flowers will ever be the same height, set the two equations equal to each other:
\[
12.2x + 16 = 8.9x + 16
\]
Subtract \( 8.9x \) and \( 16 \) from both sides:
\[
12.2x - 8.9x = 16 - 16
\]
Simplify:
\[
3.3x = 0
\]
Solve for \( x \):
\[
x = 0
\]
This means the flowers are the same height only at the time they are planted (\( x = 0 \)). After that, their heights will differ because their growth rates are different.
Final Answer
The \( y \)-intercept represents the height of the flower when planted. The flowers will be the same height only at the time they are planted (\( x = 0 \)).