Number name for 43,080,700

Maria donates a fixed amount, a, to a charity each month. if she donates $300 in 12 months, what is the equation for a? a. a + 300 = 12 b. a × 300 = 12 c. a × 12 = 300 d. a + 12 = 300 e. a + 32 = 100

Find the center and the radius of the circle with the equation: x^2-2x+y^2+4y+1=0?

What is the simplified form of (3.25x10^3)(7.8x10^6) written in scientific notation?