The question asks to analyze the mathematical expressions written on the blackboard. Based on the visual information, please list all the equations and any associated numbering or text.

Mathematical Expressions on the Blackboard:

• \[ y = x^2 + c \]
• \[ y = (x - 7)^2 \]
• \[ y = x^2 + 5 \]
• \[ y = x^2 - 12 \]
• \[ y = (x + 1)^2 \]
• \[ y = -x \]
• \[ y = (x - 8)^2 \]

Associated Numbering and Text:

• The equations on the right side are numbered vertically from 1 to 6.
• Above the first equation, there is handwritten text that appears to be "2 лист" which translates to "2 sheet" or "2 page".
• There is also some scribbled text/symbols above "2 лист".
• Above the mathematical expressions, there are headers in Russian: "Парные звонкие/глухие" (Paired voiced/voiceless), "ду глухие согласные звуки" (for voiceless consonants), and "Непарные глухие" (Unpaired voiceless). Below these headers are checkboxes and text in Russian, indicating "Всегда твердые звуки" (Always hard sounds) and "Всегда мягкие звуки" (Always soft sounds).