Dany jest ciąg arytmetyczny...Suma dwudziestu początkowych wyrazów tego ciągu jest równa 20𝑎21 + 62

Task 31. (0–2) Given an arithmetic sequence (𝑎n), defined for all natural numbers 𝑛≥1. The sum of the first twenty terms of this sequence is equal to 20𝑎21 + 62. Calculate the common difference of the sequence (𝑎n). 👉 Additional exam date. 📅 Date: June 2, 2021 Subject: Mathematics 📏 📐 ➗ ✖️ ➖ ➕ 🎓 🎓 Basic Level Tips, advice, and solutions. When explaining the problems, I assume that you can add, subtract, multiply, and divide. You are familiar with fractions and how the above operations work with them. You can solve simple equations. I solve the problems live, meaning I don't record them multiple times. Only once. That's why I sometimes stumble, think of something :) and make a mistake ;) A monster on the horizon.👾 How to master math? Math is stupid and I don't understand a thing. Do these words sound familiar to you? I have good news for you, math is manageable! Just like with sports, drawing, running, or fishing, the beginning is scary and you never want to leave the house and start running, but the further you go, the easier it gets. With math, it's totally, totally identical! At first, it's a struggle, but then, after you understand the basic rules and basic words and phrases, just like in a foreign language, it gets easier! And that's what this series is for: to learn something cool about math in a short time :) 💣 🧨 Warning! A lot of knowledge, free of charge! 📓 📔 📒 📕 📗 📘 📙 📚 📖 📹 🎥 📽 🎞Below, I've prepared a playlist of exercises especially for you. Often, it's a supplement to the topic I cover in the video, and sometimes it's just material that's good to know 🧐 🤓: ▶️ Review for the Matura exam in basic math:    • powtórka do matury z matematyki   ▶️ Matura live:    • MATURALNY MATEMATYCZNY LIVE   ▶️ Powers    • Potęgi szkoła podstawowa i liceum   ▶️ Logarithms    • logarytmy   ▶️ Trigonometry    • funkcja trygonometryczna TRYGONOMETRIA   ▶️ Combinatorics: i.e., problems like how many three-digit numbers are there, etc., rolling a die, etc.    • kombinatoryka   ▶️ Writing an expression using the letter n, i.e., write an integer divisible by 3, Write down an even number https://www.youtube.com/playlist?list...    • procenty   ▶️Fractions:    • ułamki zwykłe   ▶️Short multiplication formulas:    • wzory skróconego mnożenia   ▶️Deleting Irrationalities:    • usuwanie niewymierności z mianownika   ▶️Dice Rolling - How to Understand It? How to Record It?    • Rzut kostką   ▶️Mathematical glossary: ​​what is a natural number, an integer, a rational number, an irrational number, a real number    • słowniczek matematyczny   ▶️Excluding a common factor:    • Wyłączanie, wyciągania wspólnego czynnika ...   ▶️Function Linear:    • Funkcja liniowa   ▶️Quadratic function:    • Funkcja kwadratowa   ▶️Proofs from planimetry, algebra, angles List 1    • dowody z figurami, planimetria, kąty szkoł...   List 2    • dowody algebra, planimetria, kąty  liceum   ▶️Matura exam in mathematics, May 2020, solutions and Tips    • 05.05.2020 matura matematyka podstawowa 09...   ▶️Basic Matura Exam in Mathematics August/September 2020 Solutions and Tips    • 2020 matura poprawkowa z matematyki wrzesień   ▶️Basic Matura Exam in Mathematics August 2019 Solutions and Tips    • 2019 sierpień matura POPRAWKOWA z matematyki   ▶️Trial Matura Exam in Mathematics March 2021 Solutions and Tips Tips    • marzec 2021 matura próbna cke matematyka p...   ▶️Basic Matura exam in mathematics May 2021 solutions and tips    • MAJ 2021 Matura Z MATEMATYKI POZIOM PODSTA...   ▶️LUBELSKA PRE-MATURA TRIAL 2021 – basic level February 24, 2021    • LUBELSKA PRÓBA PRZED MATURĄ 2021 – poziom ...   ▶️Trial Matura exam with OPERON Matura Operon 2020 November basic level solutions and Tips    • Matura Operon 2020 listopad poziom podstawowy   ▶️Trial exam with OPERON Matura Operon 2020, March, basic level, solutions and tips    • Matura z Operonu matura próbna marzec 2020...   ▶️Trial exam with OPERON Matura Operon 2018, basic level, solutions and tips    • 2018 operon matura podstawowa próbna