Question

A gardener planted a newly sprouted oak tree that was just 3.5 inches tall. The sapling grew 12 inches each year.

Write an equation that shows how the sapling's height in inches, y, depends on the number of years since it was planted, x.

Answer 1

• y = 12x + 3.5

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Initial height is the y-intercept of the line.

Yearly growth rate is the slope.

So we have:

• m = 12, b = 3.5.

The equation of the line with these constants is:

• y = mx + b
• y = 12x + 3.5