Answer:
see below
Step-by-step explanation:
1. 0 = (r + 1)(r + 8)
Using Zero Product Property, r = -1, r = -8
2. h(r) = (r + 1)(r + 8)
= r² + 9r + 8
= (r + 9/2)² - 81/4 + 8
= (r + 4.5)² - 12.25 (Complete the square)
Vertex: (-4.5, -12.25)
Answer: 25
Step-by-step explanation:
Plug in x to the expression.
When there is the same base of exponents is being multiplied the exponents add together and the base stays the same.
So this simplifies to, 
.
This then solves to 25.
Answer:
7/40
Step-by-step explanation:
There are 3 girls+9 boys = 12 students in the 7th grade
P (girl in 7th grade) = girls/ total
= 3/12 = 1/4
There are 7 girls+3 boys = 10 students in the 8th grade
P (girl in 8th grade) = girls/ total
= 7/10
P(7th grade girl, 8th grade girl) = 1/4 * 7/10 = 7/40
