Answer:
Step-by-step explanation:
The standard form of a circle's equation is
where h and k are the circle's center and r is the radius. We are told, and we can see, that the center of the circle is (0, 0) so h = 0 and k = 0. The radius, given as 4, goes into the equation squared, so the equation is
which simplifies down to
, choice C.
Answer:
A
Step-by-step explanation:
Recall that for a quadratic equation of the form:
The number of solutions it has can be determined using its discriminant:
Where:
- If the discriminant is positive, we have two real solutions.
- If the discriminant is negative, we have no real solutions.
- And if the discriminant is zero, we have exactly one solution.
We have the equation:
Thus, <em>a</em> = 2, <em>b</em> = 5, and <em>c</em> = -<em>k</em>.
In order for the equation to have exactly one distinct solution, the discriminant must equal zero. Hence:
Substitute:
Solve for <em>k</em>. Simplify:
Solve:
Thus, our answer is indeed A.
Answer:
C
Step-by-step explanation:
7.1 is ten times smaller than 71
Answer:
∞
Step-by-step explanation:
I assume you meant 3×10 + 3456/3629 + 2341×123 + 123 ∞×90 and x is multiplication and not a variable.