(I) ![3x + 2y = 45](https://tex.z-dn.net/?f=3x%20%2B%202y%20%3D%2045)
(II) ![4x - y = 5](https://tex.z-dn.net/?f=4x%20-%20y%20%3D%205)
Get
alone in equation (II)
![4x - y = 5\\y = 4x - 5](https://tex.z-dn.net/?f=4x%20-%20y%20%3D%205%5C%5Cy%20%3D%204x%20-%205)
Insert new equation (II) in equation (I)
![3x + 2(4x - 5) = 45\\3x + 8x - 10 = 45\\3x + 8x = 45 + 10\\11x = 55\\x = 5](https://tex.z-dn.net/?f=3x%20%2B%202%284x%20-%205%29%20%3D%2045%5C%5C3x%20%2B%208x%20-%2010%20%3D%2045%5C%5C3x%20%2B%208x%20%3D%2045%20%2B%2010%5C%5C11x%20%3D%2055%5C%5Cx%20%3D%205)
Insert
in equation (II)
![y = 4 \cdot 5 - 5\\y = 20 - 5\\y = 15](https://tex.z-dn.net/?f=y%20%3D%204%20%5Ccdot%205%20-%205%5C%5Cy%20%3D%2020%20-%205%5C%5Cy%20%3D%2015)
Answer:
≈ 18.3 m²
Step-by-step explanation:
The shaded area (A) is calculated as
A = area of sector - area of right triangle
area of sector = area of circle × fraction of circle
A = πr² × ![\frac{90}{360}](https://tex.z-dn.net/?f=%5Cfrac%7B90%7D%7B360%7D)
= π × 8² ×
= 64π ×
= 16π m²
area of triangle =
× 8 × 8 = 4 × 8 = 32 m²
shaded area is then
A = 16π - 32 ≈ 18.3 m² ( to the nearest tenth )
2b^2 + 81/2 b + 4
basically 2b^2 + 16b + 49/2 b + 4
= (2b^2) + 16b+49/2b) + (4)
= 2b^2 + 81/2 b + 4