Среднее арифметическое ряда, который состоит из четырех чисел, равно 12. К этому ряду дописали число х. Найдите х, если среднее арифметическое нового ряда чисел равно 13.

Мне  нужно перевести дословно вот эти четыре текста:

Akiane Kramarik is a girl from a small town in Idaho whose favourite hobby is painting, s Akiane is very creative and learnt how to use pastels when she was six. She pays a lot of attention to detail and her paintings are very realistic. She finished 40 paintings that sold for as much as $25,000. 

in december 2011 raynece leader-thompson who was a student at edison middle school had to do a science project. her mother helped her desigh a game which makes learing maths simple as well as fun ! raynece got an "a" grede for project so her teacher gave it to some younger students to try out . soon after that people started to ask for their own copy of the game . so they set up a company called math works llc 

esteban cortezar is a young man whosw love for fashion began when he was a child in colombia . he began designing when he was ten . he used to take old clothes apart and then staple piecis back together again. today esteban is in charge of a growing fashion empire . he recently travelled to new york where he showed his latest collection during fashion week . esteban iis determined to succed and it looks like he is going the right way about it! 

chase austin competed in his first race at the age of eight in a go-kart pieced together by his father. the 16-year-old certainly loves speed and already has a career which many people could be jealous of . this young man from kansas is not afraid of hard work and that"s why he has won so many awards.

Заранее благодарю.

Грибы-удивительные растения.Определить падеж имён существительных.