A circle in the standard (x, y) coordinate plane is tangent to the x-axis at 5 and tangent to the y-axis at 5. Which of the following is an equation of the circle?
A.x 2 + y 2 = 5
B. x 2 + y 2 = 25
C. (x-5)} +(y-S)*=5
D. (x-5)* +(v-5)* = 25
E. （x+5）+（1+5）=25
B. x 2 + y 2 = 25
To understand why this is the correct answer, we can reason as follows:
Since the circle is tangent to the x-axis at 5, the center of the circle must be at a distance of 5 units from the x-axis. This means that the y-coordinate of the center is 5 units away from the x-axis. Similarly, since the circle is tangent to the y-axis at 5, the x-coordinate of the center must be 5 units away from the y-axis.
Since the radius of the circle is also 5 units, we can easily see that the equation of the circle is x^2 + y^2 = 5^2 = 25.