answers graded A+
distance formula - correct answer ✔✔
midpoint formula - correct answer ✔✔
equation of a circle - correct answer ✔✔
domain of a fraction - correct answer ✔✔ bottom should not equal 0
domain of a square root - correct answer ✔✔ even: greater than or equal to 0; odd: IR
domain of a polynomial - correct answer ✔✔ IR
slope - correct answer ✔✔
slope-intercept equation - correct answer ✔✔
point-slope equation - correct answer ✔✔
parallel lines - correct answer ✔✔ m1=m2
perpendicular lines - correct answer ✔✔ m1 x m2 = -1