Answer:
Plug the formula in to your calculator
2x^2-8x-24=0
Divide the whole equation by 2.
x^2-4x-12=0
Complete the square
x^2-4x+4-16=0
(x-2)^2 -16=0
(x-2)^2=16
Take the square root of each side.
(x-2)=4 and (-(x-2))=4
x=6 and x=-2
The tree was approximately 40.8ft tall.
You use the equation, a^2+b^2=c^2.
12^2 + 39^2 = x^2, add the results of 12^2 and 39^2 to make 1665 = x^2. You can take the positive root of both sides, 3√185, and it equals 40.80441152, which is rounded to 40.8.
To check if this point lies on the line, plug in a 2 for x and a y for 1 and solve
x+2y=5
2+2(1)=5
4=5
Since this statement isn't true, then the point doesn't lie on the line
Hope this helps
