Answer:
b
Step-by-step explanation:
The equation of a circle centred at the origin is
x² + y² = r² ← r is the radius
The circle shown is centred at the origin and has a radius of 5, thus
x² + y² = 5² ⇒ x² + y² = 25 → b
Answer:
y =
x² - x + 
Step-by-step explanation:
The equation of a parabola in vertex form is
y = a(x - h)² + k
where (h, k) are the coordinates of the vertex and a is a multiplier
Here (h, k) = (1, 3 ), thus
y = a(x - 1)² + 3
To find a substitute (- 1, 5) into the equation
5 = a(- 1 - 1)² + 3 ( subtract 3 from both sides )
2 = 4a ( divide both sides by 4 )
a =
, thus
y =
(x - 1)² + 3 ← expand factor using FOIL
y =
(x² - 2x + 1) + 3 ← distribute parenthesis
=
x² - x +
+ 3
=
x² - x + 
Answer:
9.90
Step-by-step explanation:
a2+b2=c2
(7)2+(7)2=c2
49+49=c2
98=c2
√98=√c2
9.90=c