Answer:
B
Step-by-step explanation:
The equation of a circle in standard form is
(x - h)² + (y - k)² = r²
where (h, k) are the coordinates of the centre and r is the radius
To obtain this form use the method of completing the square
Given
x² - 8x + y² - 2y - 8 = 0 ( add 8 to both sides )
x² - 8x + y² - 2y = 8
add ( half the coefficient of the x/y terms )² to both sides
x² + 2(- 4)x + 16 + y² + 2(- 1)y + 1 = 8 + 16 + 1
(x - 4)² + (y - 1)² = 25 → B
Answer:
(2, -1)
Step-by-step explanation:
because that's where the lines intersect
Answer:
See explanation
Step-by-step explanation:
Let x be the number of hours per week Nando is brisk walking and y be the number of hours per week Nando is biking at a moderate pace.
For the first month, he needs to exercise at most five hours per week, then

Brisk walking burns about 350 calories per hour, then it burns 350x calories per x hours.
Biking at a moderate pace burns about 700 calories per hour, then it burns 700y calories per y hours.
Nando must burn at least 2,000 calories per week, so

You get the system of two inequalities:

The attached graph shows the solution set to this system of inequalities. In this diagram, red region represents the solution set to the first inequality, blue region represents the solution set to the second inequality and their intersection is the solution set to the system of two inequalities.
1m=100cm
85 cm
400 mm=40 cm
Add up them up and you get 225 cm in total