Answer: 2
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Explanation:
x = number of years
y = height in feet
The equation for the first tree is
y = x+3
The slope is 1 to represent a rate of 1 ft per year of growth. The y intercept of 3 is the starting height. Refer to y = mx+b form.
For the second tree, the equation is:
y = 0.5x+4
This time we have a slope of 0.5 and a y intercept of 4.
Apply substitution to solve for x
y = x+3
0.5x+4 = x+3
0.5x-x = 3-4
-0.5x = -1
x = -1/(-0.5)
x = 2
The trees will be the same height in 2 years.
What will that height be? Plug x = 2 into either equation to find y. We should get the same y value.
y = x+3
y = 2+3
y = 5
Or we could say
y = 0.5x+4
y = 0.5*2+4
y = 1+4
y = 5
We've shown that both equations lead to y = 5 when x = 2. This means that at the 2 year mark, both trees are 5 feet tall. This helps confirm we have the correct x value.
