Answer:
-5
Step-by-step explanation:
3x²y + xy²
Let x = -1/2 and y = 4
3(-1/2)^2 (4) + (-1/2) (4)^2
Exponents first
3(1/4) (4) + (-1/2) 16
Multiply
3 - 8
Subtract
-5
I believe he should add 2ft to the height of the tree as well
Add the numbers and divide by 5 to get a mean of 6.4
8 - 6.4 = 1.6
4 - 6.4 = -2.4
7 - 6.4 = 0.6
8 - 6.4 = 1.6
5 - 6.4 = -1.4
Add the absolute value of each: 1.6 + 2.4 + 0.6 + 1.6 + 1.4 = 7.6
Divide by 5 = 1.52
1.5