Write the equation in standard form

- Write the equation in standard form for the circle x2+y2–16=0
- Write the equation in standard form for the circle x2+y2–9=0
- Write the equation in standard form for the circle x2+y2–4=0
- Write the equation in standard form for the circle x2+y2–1=0
- Write the equation in standard form for the circle x2+y2–49=0
- Write the equation in standard form for the circle x2+y2–36=0
- Write the equation in standard form for the circle x2+y2–25=0