X + 4y = -9 . . . (1)
2x + 5y = -6 . . . (2)
From (1): x = -9 - 4y . . . (3)
Substituting (3) into (2) gives, 2(-9 - 4y) + 5y = -6
-18 - 8y + 5y = -6
Required equation is -18 - 3y = -6
The answer to the question is b
Answer: three sets of value show 3 consecutive increases and they could be the intensities during fourth, fifth, and six visits:
- 66%, 69%, 72%;
- 63%, 65%, 67%, and
- 67%, 72%, 77%
Explanation:
1) The program recommends a constant intensity for 3 visits, which is what the table shows:
Day Intensisty
1 63%
2 equal ⇒ 63%
3 equal ⇒ 63%
2) Hence, you have to determine the valid sets that meet the recommendation for the fourth, fifth, and six visits, which are the next three.
2) For the next three visits, the program recommensd increasing intensities.
There are three options that show 3 consecutive increases; they are:
- 66%, 69%, 72%;
- 63%, 65%, 67%, and
- 67%, 72%, 77%
Therefore, those are the choices that apply.
Answer:
7π cm² ≈ 22.0 cm²
Step-by-step explanation:
The shaded area is the difference between the area of Circle B and the areas of Circle C and Circle O. That is, those white areas are subtracted from the area of Circle B to get the shaded area.
The formula for the area of a circle is
A = πr²
Using this, we find ...
Circle B area = π(3 cm)² = 9π cm²
Circle C area = Circle O area = π(1 cm)² = π cm²
Then the shaded area is ...
Shaded Area = Circle B area - Circle C area - Circle O area
= (9π cm²) - (π cm²) - (π cm²)
= 7π cm² ≈ 22 cm²
