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.
A Brigham and Women's Hospital answered. Depo-Provera is a hormone injection used for birth control. It is administered starting within the first five days of your period, then every 12 weeks thereafter. Working similar to a birth-control pill, Depo-Provera has the hormone progestin, which changes the lining of the uterus, making it difficult for sperm to fertilize an egg. In the weeks between shots, you do not have to use other contraceptive methods. It is 99% effective in preventing pregnancy.