Linear equation - One variable. 1  A linear equation in one unknown x may always be rewritten. 2  If a â  0, there is a unique solution. 3  If a = 0, then, when b = 0 every number is a solution of the equation, but if b â  0 there are no solutions (and the equation is said to be inconsistent.)
How effective is the Depo shot? The birth control shot â Depo-Provera â is one of the most effective methods of birth control available. Each shot of Depo-Provera will protect you from pregnancy for 12 weeks. It works best when you get the birth control shot regularly, every 12 weeks. Fewer than one out of 100 women will get pregnant each year if they always use the birth control shot as directed. About six out of 100 women will get pregnant each year if they donât always use the birth control shot as directed.
With typical use, hormonal birth control is about 90% effective. But if used correctly all the time, it prevents pregnancy over 99% of the time. The implant is also about 99% effective. If you decide to take a birth control pill, ask your doctor how long you should use another form of birth control until the pill takes effect. Barrier Birth Control As the name suggests, these create a barrier to keep sperm from reaching an egg.