Question 273583: i'm having troubles with worded linear equations
a gardener once noticed that her daffodils were 12cm tall and then that they grew steadily by 1.6cm per day for the next 10 days,
how would you write an equation for this ?
Answer by Theo(13342)   (Show Source):
You can put this solution on YOUR website! let x = amount of days that went by.
let y = the height of the daffodils.
equation would be:
y = 12 + 1.6 * x
when x = 0, they are 12 cm
when x = 1, they are 12 + 1.6 cm
when x = 2, they are 12 + 3.2 cm
a graph of your equation would look like this:
I placed a horizontal line at y = 12 and y = 28 so you can see that when x = 0, y = 12, and when x = 10, y = 28.
To trace that, you need to draw a vertical line from the intersection points down to the x-axis.
The vertical line when x = 0 is the y-axis.
Each x represents 1 day.
I have to show negative values because the graph won't display properly without them.
You read the graph by looking at the y values from x = 0 and working your way to the right until x = 10.
the domain of your function would be x = 0 to 10
the range of your function would be y = 12 to 28
I placed a horizontal line at y = 20.
trace an imaginary vertical line down from there and you should intersect the x-axis at around 5.
The other way to check is to plot the points.
You do that by solving the equation at the selected points.
How tall were the daffodils after 5 days?
The value would be y = 12 + (1.6*5) = 12 + 8 = 20 cm.
At the start, the value of y would be 12 + (1.6 * 0) = 12 + 0 = 12
After 10 days, the value of y would be 12 + (1.6 * 10) = 12 + 16 = 28
The slanted line is the graph of your equation.
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