In math what is imaginary i stand for

According to modern science, earth is about 4.5 billion years old and written human history extends back about 10,000 years. suppose the entire history of earth is represented with a 10-meter-long timeline, with the birth of earth on one end and today at the other end.

How are sas and sss used to show that two triangles are congruent?

Sandy is upgrading her internet service. fast internet charges $20 for installation and $52.45 per month. quick internet has free installation but charges $57.45 per month. part 1 out of 2 complete the equation that can be used to find the number of months after which the internet service would cost the same. use the variable x to represent the number of months of internet service purchased.