Answer:
5 hours
Step-by-step explanation:
This is a classic pre-algebra question.

Answer:
140°
Step-by-step explanation:
<3 = 40 because they are vertical angles
<3 +<4 = 180 because they are same side interior angles
40 + <4 = 180
Subtract 40 from each side
40-40 + <4 = 180-40
<4 = 140
Fraction is used to rename 5/6
Answer:
5 millicuries
Step-by-step explanation:
Half life is 7 days which means it will be at 10 millicuries if we half that again for another 7 days then it will be 5.
We are told that f(x) = x + 2. We want to find
.
Squaring f(x) on one side means we square x + 2 on the other.
So,
f(x) = x + 2
(f(x))² = (x + 2)²
= (x + 2)(x + 2)
We can use FOIL to square x + 2. The first terms multiply to x², the outside terms to 2x, the inside terms to 2x and the last terms to 4.
= x² + 2x + 2x + 4
= x² + 4x + 4
So [f(x)]² = x² + 4x + 4